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ZT52HD DECK VIBRATION FIX

#1

S

sbrilla11

Guys, after going to 2 dealers last fall and finding no solution for the deck vibrations (harmonics) I finally got my 52 HD out and decided to fix it on my own. After looking over it was obvious it was related to the tensioner. If you look at the way the arm was designed the pivot point gives the idler pulley twice as much mechanical advantage over the spring. I ended up machining a new arm with pivot point that is twice distance giving the spring the mechanical advantage. The vibrations are about the same however the horrible noise is now gone! The spring vibrates half as much as it used to. If you guys are interested I can post a picture of what I did.


#2

B

bassadict69

Please do...


#3

C

Cphillips82

sbrilla11 said:
Guys, after going to 2 dealers last fall and finding no solution for the deck vibrations (harmonics) I finally got my 52 HD out and decided to fix it on my own. After looking over it was obvious it was related to the tensioner. If you look at the way the arm was designed the pivot point gives the idler pulley twice as much mechanical advantage over the spring. I ended up machining a new arm with pivot point that is twice distance giving the spring the mechanical advantage. The vibrations are about the same however the horrible noise is now gone! The spring vibrates half as much as it used to. If you guys are interested I can post a picture of what I did.
Click to expand...

Please post im having this issue too!


#4

G

gravelyzthd52

Please post details!

Thanks


#5

C

Cphillips82

gravelyzthd52 said:
Please post details!

Thanks
Click to expand...

Too bad he wont respond to us. Was curious does it seem like with yours there is too much belt slack? It seems like potentially the main issue may be that the excessive slack in the belt causes the entire deck to vibrate too much. Theres several moments where the belt isnt whipping so much when the rattle/vibration stops and then it starts flopping around more and it rattles the whole mower. Is there a way to tighten the belt? Might be an easy fix if we can.


#6

C

Cphillips82

I was just out tinkering with it. I attached a small rope to the left side deck spring and pulled on it to create more tension on the belt while the blades were engaged. I found that this greatly reduced the noise. So now I'll speak with the dealer in the morning to get his thoughts on this. Bad spring or belt maybe?


#7

C

Cphillips82

The plot thickens...I just spoke with a different dealer than the one I bought mine from. Because this dealer sells so many Gravely's they speak frequently with higher ups at Gravely and there IS FOR SURE AN ISSUE WITH THE 52" ZT HD. The 60" and 48" don't make the rattle but it is a common complaint that Gravely is aware of (though they probably won't admit it now until there's a fix). The person I spoke with was very helpful and took a lot of time to talk with me despite it being of no benefit to them. She will give me a call as she finds out more and if there becomes a recall.


#8

C

Cphillips82

I've posted a video of my rattle noise on youtube. Search Gravely zt hd 52 rattle noise and you'll see it. I also sent it to Arien's support 2 weeks ago and just got a call today from someone at Ariens. He wasn't sure what the issue is exactly but recognized that it's not normal and was going to contact my dealer on my behalf to get it in for service and figure out the problem. He was just guessing but thought perhaps it was a problem with that belt or perhaps one of the pulleys has an issue. I feel relieved now at least having someone from the company trying to help me get it fixed. If/when the dealer figures out the problem I will post again.


#9

T

tbzep

Thanks for posting the video. I was beginning to wonder if my HD52 had the same issue and I was just oblivious to it. I'm happy to say mine isn't doing that so it doesn't happen with all of them.


#10

C

Cphillips82

tbzep said:
Thanks for posting the video. I was beginning to wonder if my HD52 had the same issue and I was just oblivious to it. I'm happy to say mine isn't doing that so it doesn't happen with all of them.
Click to expand...

If you get a chance would you mind looking at your left side deck belt with the blades engaged and seeing if it has as much slack as mine does in my video? Would be much appreciated.


#11

G

gravelyzthd52

Cphillips82 said:
I've posted a video of my rattle noise on youtube. Search Gravely zt hd 52 rattle noise and you'll see it. I also sent it to Arien's support 2 weeks ago and just got a call today from someone at Ariens. He wasn't sure what the issue is exactly but recognized that it's not normal and was going to contact my dealer on my behalf to get it in for service and figure out the problem. He was just guessing but thought perhaps it was a problem with that belt or perhaps one of the pulleys has an issue. I feel relieved now at least having someone from the company trying to help me get it fixed. If/when the dealer figures out the problem I will post again.
Click to expand...

I just watched your video and that is the same exact noise mine makes. I will check mine tomorrow to see if there is as much slack in the belt as yours. I contacted Gravely and they simply referred me to my dealer who I just haven’t been able to coordinate a time with - my fault. They said that this is not a widespread issue. Would you mind sending me a PM with the persons name or contact info who called you? All I got was an email.


#12

G

gravelyzthd52

Here is a link to my video on YouTube. Will check the belts today.

https://youtu.be/0cinjlT9R3g


#13

G

gravelyzthd52

Here is my second video showing the belts, etc. during deck rattle/vibration. A LOT of slop in the belt and A LOT of movement going on in there.

https://youtu.be/GsV24nnC_Sk

Can someone who doesn’t have this issue take a video of their deck so we can see the difference?


#14

cpurvis

cpurvis

gravelyzthd52 said:
Here is a link to my video on YouTube. Will check the belts today.

https://youtu.be/0cinjlT9R3g
Click to expand...

Does that spring have clearance all around it or is it touching metal somewhere?


#15

G

gravelyzthd52

cpurvis said:
Does that spring have clearance all around it or is it touching metal somewhere?
Click to expand...

It’s not touching anything. At first I thought that’s what the issue was but it doesn’t seem to be touching anything.


#16

cpurvis

cpurvis

Watching the videos, it seems that spring's biggest side-to-side vibrations coincide really well with the noise. It's as if the spring is hitting it's resonant frequency. I'm not sure if the spring itself can make the noise but that spring would be the first thing I would concentrate on.


#17

J

jcc3

sbrilla11 said:
Guys, after going to 2 dealers last fall and finding no solution for the deck vibrations (harmonics) I finally got my 52 HD out and decided to fix it on my own. After looking over it was obvious it was related to the tensioner. If you look at the way the arm was designed the pivot point gives the idler pulley twice as much mechanical advantage over the spring. I ended up machining a new arm with pivot point that is twice distance giving the spring the mechanical advantage. The vibrations are about the same however the horrible noise is now gone! The spring vibrates half as much as it used to. If you guys are interested I can post a picture of what I did.
Click to expand...

I would be super interested in a picture! I recently purchased a new HD 52 ( 8.3hrs now) and I have a similar ( i think) jangling -metal to metal - noise which seems to come from the left side of top or under deck (as you look down from seat) whne PTO engaged. The dealer rep - salesman - drove back day after delivery (58 miles one way) and pronounced it OK no problems even after riding and mowing and hearing the noise so I kinda sorta fell better but its a disturbing noise.

I will try t look at the tensioner but novice eye may not recognize an issue.


#18

G

gravelyzthd52

jcc3 said:
I would be super interested in a picture! I recently purchased a new HD 52 ( 8.3hrs now) and I have a similar ( i think) jangling -metal to metal - noise which seems to come from the left side of top or under deck (as you look down from seat) whne PTO engaged. The dealer rep - salesman - drove back day after delivery (58 miles one way) and pronounced it OK no problems even after riding and mowing and hearing the noise so I kinda sorta fell better but its a disturbing noise.

I will try t look at the tensioner but novice eye may not recognize an issue.
Click to expand...

Contact Gravely and point them to this thread. They need to know that more people have this issue and they can also contact the dealer on your behalf. Gravely emailed me the other day with a list of possible issues that could be causing the noise that they will recommend my dealer looks at.


#19

J

jcc3

I've contacted Gravely and opened a case and I've added my experience. Hope there's some useful feedback from Gravely - my dealer heard the same noise rattling and said "belts just need to wear in - you're OK".


#20

C

Cphillips82

Wow well theres definitely a couple of us now! I haven't gotten mine in for service here yet as I've been too busy and I actually havent had to mow much as its a bit of a drought here in NY but I'm going to try to call back that guy that contacted me from Ariens/Gravely and let him know about this thread.


#21

C

Cphillips82

Fueled Iowa posted a video on youtube about a rattle fix he had: https://www.youtube.com/watch?v=pF3QlSNvFF4

This fix has to do with the deck cover making contact with that bolt underneath it which isn't the same issue as mine but he does also mention at the end of the video that he had his clutch replaced when he first got it due to a "resonance shimmy or shake" when the pto was engaged and THAT does sound a lot like my issue. His dealer ended up replacing it only after they couldn't find anything else to try but it ended up being the fix.


#22

J

jcc3

This fix has to do with the deck cover making contact with that bolt underneath it which isn't the same issue as mine but he does also mention at the end of the video that he had his clutch replaced when he first got it due to a "resonance shimmy or shake" when the pto was engaged and THAT does sound a lot like my issue. His dealer ended up replacing it only after they couldn't find anything else to try but it ended up being the fix.

The grommet wouldn't solve my problem since I dont think it would stop the belt from the violent flapping around but the clutch replacement is interesting?


#23

C

Cphillips82

jcc3 said:
This fix has to do with the deck cover making contact with that bolt underneath it which isn't the same issue as mine but he does also mention at the end of the video that he had his clutch replaced when he first got it due to a "resonance shimmy or shake" when the pto was engaged and THAT does sound a lot like my issue. His dealer ended up replacing it only after they couldn't find anything else to try but it ended up being the fix.

The grommet wouldn't solve my problem since I dont think it would stop the belt from the violent flapping around but the clutch replacement is interesting?
Click to expand...

Dealer is picking mine up tomorrow and they plan to take their time going through it. I will keep you guys posted.


#24

cpurvis

cpurvis

Friend of mine just bought a new Gravely 52" and his mower is in the shop for the same problem. He's getting different opinions from people at the dealership but he finally told them not to return it to him making that noise--either fix it or refund his money.


#25

C

Cphillips82

cpurvis said:
Friend of mine just bought a new Gravely 52" and his mower is in the shop for the same problem. He's getting different opinions from people at the dealership but he finally told them not to return it to him making that noise--either fix it or refund his money.
Click to expand...

Yeah I dont blame him. Any idea if theyve considered replacing the pto clutch?


#26

cpurvis

cpurvis

Cphillips82 said:
Yeah I dont blame him. Any idea if theyve considered replacing the pto clutch?
Click to expand...
No, I haven't talked to him for over a week.


#27

C

Cphillips82

cpurvis said:
No, I haven't talked to him for over a week.
Click to expand...

Let him know about this thread when you get a chance, hopefully we will all get a fix eventually.


#28

J

jcc3

cpurvis said:
Friend of mine just bought a new Gravely 52" and his mower is in the shop for the same problem. He's getting different opinions from people at the dealership but he finally told them not to return it to him making that noise--either fix it or refund his money.
Click to expand...

Sounds like it is newly purchased machine ? Mine is 34 days old. I am thinking to do the same but I'll have to check return policy at dealer before dumping it at their doorstep as I would like to do.


#29

cpurvis

cpurvis

Cphillips82 said:
Let him know about this thread when you get a chance, hopefully we will all get a fix eventually.
Click to expand...
He doesn't do the internet but I'm relaying anything I find out to him. I've already told him that it's a systemic problem, not something that's peculiar to his mower.


#30

B

bertsmobile1

While not being a Gravely, I had a similar sort of thing happen with a Dixie Chopper.
The Idlers went so I replaced them with a pair of similar size because the owner did not want to fork out $ 176 for genuine pulleys.
The tensioning pulley was smaller then the original by about 1/2" , not much on a very long belt.
Don't know why but even when I tightened the spring a few turns, the belt slapped around like one of the pulleys was oval.
I wondered if the pulley was not made correctly & the bearing was not concentric with the working face so I fitted a bigger pulley because that was all I had on hand and the belt ran smooth as silk, so we left it like that.
The suspect pulley went onto a Z master for a commercial customer to keep him on the road, worked fine so is still on there.

So it might be nothing more than a bad combination of pulley sizes , belt tensions & springs.


#31

C

Cphillips82

bertsmobile1 said:
While not being a Gravely, I had a similar sort of thing happen with a Dixie Chopper.
The Idlers went so I replaced them with a pair of similar size because the owner did not want to fork out $ 176 for genuine pulleys.
The tensioning pulley was smaller then the original by about 1/2" , not much on a very long belt.
Don't know why but even when I tightened the spring a few turns, the belt slapped around like one of the pulleys was oval.
I wondered if the pulley was not made correctly & the bearing was not concentric with the working face so I fitted a bigger pulley because that was all I had on hand and the belt ran smooth as silk, so we left it like that.
The suspect pulley went onto a Z master for a commercial customer to keep him on the road, worked fine so is still on there.

So it might be nothing more than a bad combination of pulley sizes , belt tensions & springs.
Click to expand...

Yeah I think you may very well be right, its just strange that some owners dont have the noise but many do. So inconsistencies at the factory with placement or parts? IDK


#32

C

Cphillips82

Just a reminder to anyone reading this if you have the same issue COMPLAIN TO GRAVELY SUPPORT ABOUT IT!


#33

G

gravelyzthd52

My dealer came to my house today to check out the noise from my deck. After looking at a bunch of different things we may have figured out what is causing the noise on my mower. There is part of the lift arms on the front of the deck that are connected between two brackets on the deck housing. When he wedged a long metal nail set between the linkage and the deck brackets the noise stoped. When he took the nail set out it would be ok for a few seconds but then start up again. He took some pictures of the brackets and is going contact Gravely on Monday to see what they say about it. It really was interesting because when he wedged that in there there was no noise at all, just the beautiful sound of mower blades spinning at high RPM’s. I really hope this is the problem and they can come up with some fix for it.

In the pictures of both right and left side you can see where the rod is touching the bracket on one side. Would be interesting to see if someone else can make the noise stop by wedging something between the rod and the bracket on left side of the deck (if you are sitting on the mower). I will let everyone know what he hears back from Gravely.


View attachment 39094
View attachment 39095


#34

G

gravelyzthd52

Here are the pictures from my last post. They didn’t attach for some reason and I can’t edit it.

C1CBF737-3C07-41CC-BA53-50E5241BCFDA.jpg22F27513-ED00-4CF0-ABF8-7CAC33822882.jpg860D2350-3B28-4777-A9F3-92EAC1D93B3F.jpg


#35

C

Cphillips82

Thanks for posting that info. Mine is currently at my dealers being looked at so I will call them first thing Monday to have them try that and to read your post. Perhaps installing some kind of rubber insert in there or even a spray on rubber like Flexseal?


#36

B

bertsmobile1

Vibrations and resonances are weird things and a speciality field all of their own.
Deck pulley sizes are determined by pluging in loads, tensions power demands into equations that the belt makers provide.
Thus it is easy to come up with little things like a pulley mounting hole at a length on a tensioning arm that is a length that will cause resonance between the spring & the belt.
Then you get slight differences between the production prototypes and the actual production line output.
Cost structures prohibit the old days system of testing each & every one off the line and this problem could be something that requires a set amount of wear to happen before it is triggered.

Unfortunately your pictures did not seem to work.
Can you repost them or put them into a photo hosting app ?


#37

C

Cphillips82

I rewatched your youtube videos and that is definitely the same noise as mine so I’m pretty pumped that you may have figured it out!


#38

G

gravelyzthd52

bertsmobile1 said:
Vibrations and resonances are weird things and a speciality field all of their own.
Deck pulley sizes are determined by pluging in loads, tensions power demands into equations that the belt makers provide.
Thus it is easy to come up with little things like a pulley mounting hole at a length on a tensioning arm that is a length that will cause resonance between the spring & the belt.
Then you get slight differences between the production prototypes and the actual production line output.
Cost structures prohibit the old days system of testing each & every one off the line and this problem could be something that requires a set amount of wear to happen before it is triggered.

Unfortunately your pictures did not seem to work.
Can you repost them or put them into a photo hosting app ?
Click to expand...

I reposted them in a separate post above because I couldn’t edit it to fix the pictures.


#39

B

bertsmobile1

Thanks for that.
Now I got a handle on it
So looks like s heavy rubber sleeve on that shaft so it can move a little & not bang on the mountings looks to be an answer to the symptoms .
Now to tackle the cause.


#40

G

gravelyzthd52

I took a video this morning demonstrating what my dealer found yesterday while checking out my deck. I would be interested to see if other people with this issue can reproduce what I did in the video. Will send to my dealer so he can show Gravely. You can see in the video when push the round part in the noise stops instantly.

https://youtu.be/TWIK9W_LoLI


#41

S

strick

I just took delivery of a brand new HD 44. Same exact sound was coming from mine...only when the PTO is engaged. It's coming from the flip up deck plate. At least thats what was happing with mine. I notice that you have your feet all the way forward off the plate while the PTO is engaged. Try engaging the PTO and move your feet back to the middle of the plate and put pressure down with your feet and see of the noise goes away. When you lift up the deck plate in the rear there is the round bar that goes across and underneath the plate. On either side of the bar you will see where the plate has been rubbing on the bar. It's a small area on both the left and right side of the bar. I seen the rub marks in the vid on yours as well. The fix was easy on mine. I'll try and post some photos on the Lawn site you have the thred going on. Hope this helps.

strick


#42

C

Cphillips82

strick said:
I just took delivery of a brand new HD 44. Same exact sound was coming from mine...only when the PTO is engaged. It's coming from the flip up deck plate. At least thats what was happing with mine. I notice that you have your feet all the way forward off the plate while the PTO is engaged. Try engaging the PTO and move your feet back to the middle of the plate and put pressure down with your feet and see of the noise goes away. When you lift up the deck plate in the rear there is the round bar that goes across and underneath the plate. On either side of the bar you will see where the plate has been rubbing on the bar. It's a small area on both the left and right side of the bar. I seen the rub marks in the vid on yours as well. The fix was easy on mine. I'll try and post some photos on the Lawn site you have the thred going on. Hope this helps.

strick
Click to expand...

I'll check this out as well but it does look like tightening that area/part seen in gravelyzthd52's video made a big difference. My dealer tightened that as well as the other arm next to it and he though those 2 things made the biggest improvement. The noise is much quieter and doesnt whir in and out so I believe I'm happy based on a few minutes of mowing at my dealers. I'll get it back on Thursday and mow my whole yard so I'll possibly have some more feedback.


#43

J

Johnny C

This seems to be a positive development on the noise but I wonder if this has any effect on the belt - which on my machine gyrates in a fashion that would seem to put stress on the belt and make it wear/break a lot faster ?


#44

B

bertsmobile1

No.
In fact the tighter the belt the better it is for the belt.
The limiting factor on belt tightness is the cheap design of the engines which causes the output shaft hole which is also the crankshaft bearing flogging out oval


#45

S

strick

Ok here are some pictures of where the flip up deck was vibrating on the round bar that runs across the back of the deck. And how I fixed it. I added some red adhesive tape where the contact points are. Next I added some fasteners to the front of the flip up deck I got at the local Ace Hardware. The deck already has two square holes in the front on either side as if they anticipated if needing to be secured so I just drillid them out and added 2- 3/8" bolts 3/4" long with a twist on T-fastener.

strick

20180716_174037.jpg 20180716_174043.jpg 20180716_174103.jpg 20180716_175620.jpg 20180716_175652.jpg 20180716_175702.jpg

20180716_175707.jpg


#46

G

gravelyzthd52

Cphillips82 said:
I'll check this out as well but it does look like tightening that area/part seen in gravelyzthd52's video made a big difference. My dealer tightened that as well as the other arm next to it and he though those 2 things made the biggest improvement. The noise is much quieter and doesnt whir in and out so I believe I'm happy based on a few minutes of mowing at my dealers. I'll get it back on Thursday and mow my whole yard so I'll possibly have some more feedback.
Click to expand...

That’s great to hear. I’m looking forward to your feedback after mowing for a longer period of time.


#47

G

gravelyzthd52

strick said:
Ok here are some pictures of where the flip up deck was vibrating on the round bar that runs across the back of the deck. And how I fixed it. I added some red adhesive tape where the contact points are. Next I added some fasteners to the front of the flip up deck I got at the local Ace Hardware. The deck already has two square holes in the front on either side as if they anticipated if needing to be secured so I just drillid them out and added 2- 3/8" bolts 3/4" long with a twist on T-fastener.

strick

View attachment 39165 View attachment 39166 View attachment 39167 View attachment 39168 View attachment 39169 View attachment 39170

View attachment 39171
Click to expand...

Thanks Strick. I’m not sure if that is my problem though as my mower still makes the noise with foot plate up. I will definitely check though.


#48

S

strick

Sounds good I saw in the vid that it was making the noise with the plate up as well. Could be vibrating ons something else while up. Easiest way to find out if it's the deck plate is to just put firm pressure with your feet while mowing and see if it goes away. The Deck plate is the only part of the mower that does not have an attachment point on one end which makes it prone to vibration. Good luck I'll be checking back from time to time.

strick


#49

T

tbzep

strick said:
The Deck plate is the only part of the mower that does not have an attachment point on one end which makes it prone to vibration.

strick
Click to expand...
The chute can vibrate and make a little noise also.


#50

S

strick

tbzep said:
The chute can vibrate and make a little noise also.
Click to expand...

Yep and mine makes a little rattle. The deck plate was unbearable. I thinking of getting rid of the machine if I could not find the source and fix it. Now I'm happy with the machine the are very well built.

strick


#51

C

Cphillips82

Got it back last week and mowed some more. The noise is still there but definitely not as bad with all those things tightened up. I can move that same part that you did in the video when the mowers running/blades engaged and it is virtually gone if I hold it in there. I checked the deck plate and that is not an issue for me. I'd like to figure out a way to hold that bar in possibly by tying it around the inside bracket. Have you figured out a way?


#52

J

Johnny C

This vid posted on another site shows possible outboard pulley wobble which might be cause of belt movement issue that I have - I'm pulling belts tonight to check

vimeo.com/282133168 that begins with https:// (since I cant yet post links)


#53

C

Cphillips82

Johnny C said:
This vid posted on another site shows possible outboard pulley wobble which might be cause of belt movement issue that I have - I'm pulling belts tonight to check

vimeo.com/282133168 that begins with https:// (since I cant yet post links)
Click to expand...


Interesting, definitely let us know. Sure looks like it could be the actual cause. Would it just be replacement of that pulley you think?


#54

H

handtools

Cphillips82 said:
Got it back last week and mowed some more. The noise is still there but definitely not as bad with all those things tightened up. I can move that same part that you did in the video when the mowers running/blades engaged and it is virtually gone if I hold it in there. I checked the deck plate and that is not an issue for me. I'd like to figure out a way to hold that bar in possibly by tying it around the inside bracket. Have you figured out a way?
Click to expand...

I have the same sound from the 60" deck on my Ariens Apex, I could reduce or eliminate the sound by pushing on those bars so I squeezed the brackets together with vise grips to limit the movement of those bars and the noise has subsided almost completely.


#55

J

Johnny C

Cphillips82 said:
Interesting, definitely let us know. Sure looks like it could be the actual cause. Would it just be replacement of that pulley you think?
Click to expand...

Not sure if replacement of pulley is cause and resolves total issue. After a look, I am going to have dealer ( not the purchase dealer but one I found that will actually listen and help) check the bar push in solution and the pulleys / spindles. Will report back


#56

G

gravelyzthd52

No resolution yet on this. My dealer has spoken with Gravely and mentioned he wanted to take some measurements but I have not heard back on that yet. I just emailed Gravely and told them I will be requesting a full refund for the mower if this is not resolved soon. This has been going on since May with no fix, not what I expected from Gravely. I guess I should have bought an eXmark, John Deere, anything else.


#57

J

Johnny C

My dealer sent their small engine expert and repairman to the house to examine the unit today. He removed an inspected belts, checked blades, spindles and pulleys during two hours of work right in front of me in the driveway. He clearly heard and acknowledged the ringa ringa noise but could find no cause or evidence of it making impacts anywhere or doing damage. At this point I can only take his word and know that they have contacted Gravely ( as have I ) and that I am on record with them both if something significant occurs as a result of this issue later .

This may not be the right or even a good answer - in fact there IS SOMETHING causing the noise - but until Gravely or a more knowledgeable expert can identify it...... I am fumbuzzled.


#58

cpurvis

cpurvis

It's a design problem. Gravely has unwittingly designed a mower drive system that has a resonant frequency somewhere close to the operating rpm of the mower.

A friend as a new Gravely that has the noise and an old one that doesn't. I bet if the two are compared, we'll see a design change in belts, idlers or tensioners that initiated this problem. Problem is, the two mowers are 150 miles apart right now.


#59

B

bertsmobile1

Yep that is all it is, a resonance and understanding them is science at the pHd level.
Can be as simple as the position or length of a weld, the placement of a deck support the thickness of the steel a pulley is made of.
So it will take a while to locate the exact cause and then make sure the fix at A does not create a new bigger problem at B


#60

mhavanti

mhavanti

Have any of you shortened the belt tension spring to see if that helps alleviate the belt flopping around. From the video, it appears to me the belt resonance is causing all of your metal parts to sing along with the belt tensioner moving back and forth in time. Maybe find a shorter spring before you cut and reshape yours.

Let us know if that brings a halt to the maddening Gravely Clamor.

Max


#61

T

tbzep

Adding a bit of weight in strategic locations often dampens harmonic vibrations. How much and where to put it is where the voodoo comes in.


#62

C

Cphillips82

mhavanti said:
Have any of you shortened the belt tension spring to see if that helps alleviate the belt flopping around. From the video, it appears to me the belt resonance is causing all of your metal parts to sing along with the belt tensioner moving back and forth in time. Maybe find a shorter spring before you cut and reshape yours.

Let us know if that brings a halt to the maddening Gravely Clamor.

Max
Click to expand...

This was one of my first thoughts as well after I pulled on that spring to cause more tension on the belt the noise went away. I don’t know where to get a hold of another spring to try out is the problem. Not to mention if more tension is put on the belt would it wear out the belt that much faster. The biggest help for me has been keeping that bar pushed in. I stuck a rubber riser that had peal off adhesive on the bracket so that the bar cant migrate out nearly as much. I’d say the noise is around 80% better with this fix. It was also a bit better after my dealer tightened every bolt around the deck.


#63

B

bertsmobile1

You could try something like a trampoline spring ( cause they are easy to get ) pulling against the tension spring to damp out the vibrations .
Other than that cut some washers out of a milk bottle ( if they are plastic ) and use them under the tension arm pivot to load it up a little and slow down the movements.


#64

cpurvis

cpurvis

If there are any open areas on idler pulley arms, attach the heaviest magnetic weights that will fit. If this helps, attach the weights permanently.


#65

G

gravelyzthd52

My dealer has had my mower for just over a week now. He believes he knows how to resolve the problem and is waiting to hear from Gravely. He said the bracket that holds the metal pin that moves in and out is out of alignment just enough to allow the floating and then the vibrations. It stops when you push on it because by doing that you are putting tension on it as there would be if the bracket were aligned correctly. The bracket is welded onto the frame so the two options are either a new deck shell or he bends the bracket slightly to put the correct tension on the pin. I would prefer to have a deck shell that is correct from the factory so we will see what Gravely says. Dealer has been great to work with and has really taken the time to find the problem and address it. Now up to Gravely to do the same.


#66

mhavanti

mhavanti

Glad to hear your dealer is doing what he claimed he'd do when he sold you on his service. As it should be.

Hope they resolved the problem permanently for you.

Max


#67

G

gravelyzthd52

Quick update, Gravely has replaced my deck shell under warranty as they believe the misaligned bracket is causeing there not to be tension on the metal pin and allowing it to move which then causes the noise. Seeing that it could take a few weeks to get the new deck shell the dealer has given me a ProTurn 260 to use in the meantime. The 260 is an absolute beast of a machine and I may not be able to go back to the HD52! The one interesting thing though is that I think my HD52 actually cuts better than the 260. The 260 cuts fine but has a tendency to leave uncut blades of grass here and there where I don’t notice that on my HD52. Not a big deal and wouldn’t stop me from using it but just something I noticed.


#68

C

cootertwo

Nice to hear about a good Dealer, and Gravely stepping up with good customer support.:smile:


#69

cpurvis

cpurvis

I got to play with my friend's ZT52 today. I think we reduced, but didn't eliminate the vibration. We ran out of magnets before we ran out of vibration.

I noticed there is a huge amount of deflection going on with the main drive belt. The belt looks good (mower has 50 hours on it) but I can't imagine it lasting very long whipping around like that.

The belt that runs the RH spindle is a segmented belt. I wonder why? But there wasn't nearly the belt deflection or idler movement on this belt. The belt that powers the center and LH spindles is the one that is thrashing around the most.


#70

G

gravelyzthd52

*Update* my deck is fixed! No more rattling noise. The only noises I have now are just the sounds of the blades and belts which are normal. The dealer swapped the original deck shell with a brand new shell and it totally solved the problem. They said there was a bracket on the original deck that was misaligned which was allowing one of the hangers for the deck to move and then cause the rattle. I made a video of that piece moving. With the new deck shell that hanger doesn’t move anymore and there is no more rattling.

If you’re having this problem tell Gravely that you want your dealer to replace your deck shell with a new one from the factory!


#71

N

NealS

Did the new deck fix which cured the noise, have any effect on the belts flopping as seen in your video?


#72

M

my87csx481

Sorry for the thread revival.

I have a brand new 2019 ZT HD 52 that is is making the same exact noise as Fueled Iowa and Chad Phillips. I have 7 hours on the machine. It has also developed a whine when the PTO is engaged (at around the 6 hour mark).

Did a new deck shell fix the rattle issue? Does your belt still flop around wildly?

One would think they would have corrected this by now.


#73

G

gravelyzthd52

my87csx481 said:
Sorry for the thread revival.

I have a brand new 2019 ZT HD 52 that is is making the same exact noise as Fueled Iowa and Chad Phillips. I have 7 hours on the machine. It has also developed a whine when the PTO is engaged (at around the 6 hour mark).

Did a new deck shell fix the rattle issue? Does your belt still flop around wildly?

One would think they would have corrected this by now.
Click to expand...

Sorry for the delay. The rattle is pretty much gone but the deck still makes noises that are most likely just the belts and blades that I sometimes hear. I think the only reason I notice those noises though is because of the experience with the rattling as whenever I hear something I listen to see if the rattling is coming back.

Now I just need to figure out how to block debris from coming out of the front of the deck and up onto my legs and all over me. I would love to mow without getting covered in grass clippings and debris.

The ZT HD is a great mower but the flaws with the deck will probably cause me to sell it or trade it for something different soon. The Pro Turn 260 I used while mine was getting fixed was unreal but cost more than twice as much. They have a new Pro Turn ZX that isn’t too much more but it looks like it has the same exact deck. Whatever I buy I will definitely need to demo first to make sure it doesn’t have the same issues.


#74

M

my87csx481

Thanks for the reply. No need to apologize. I never thought anyone would reply back.

Just got mine back from the dealer. They warrantied the groaning spindle. Their fix for the deck rattle was to install teflon washers on the discharge chute. They claimed there are no service bulletins on it.

Some of the rattle noise is gone but, my discharge chute binds up now because they over tightened the bolts (to cover up the noise). The resonating vibration/oscillation is still there.

I saw somewhere (forum or youtube) where someone designed a new PTO belt tension arm to give the spring more mechanical leverage over the pulley. I hope I can find that again. Anyone have a link?

Edit: It was this thread. sbrilla11, please post the design, or video, or something. Thanks.

Edit2: Also, I don't find myself getting covered in clippings at all, or much on top of my deck. My deck did come delivered with the deck baffles. They are red, not black like the ones in Fueled Iowa's video. If yours did not come with them, maybe they will help?

Edit3: I have been running with the discharge chute down. I took it completely off just now (eliminating as much as I can to reduce rattles). I think I will get a small amount of clippings on me now. I'll report back over the weekend, after I mow again.


#75

cpurvis

cpurvis

I rode with my friend to take his back to the dealer in November, after the mowing season was over.

As of 6/6/2019, he still does not have it back. To the dealer's credit, they gave him a loaner to use and he's put about 50 hours on it. He doesn't like it as well, mainly because it has a Gravely brand engine which he says is hard to start. Anybody know anything about the Gravely engine?


#76

G

gravelyzthd52

my87csx481 said:
Thanks for the reply. No need to apologize. I never thought anyone would reply back.

Just got mine back from the dealer. They warrantied the groaning spindle. Their fix for the deck rattle was to install teflon washers on the discharge chute. They claimed there are no service bulletins on it.

Some of the rattle noise is gone but, my discharge chute binds up now because they over tightened the bolts (to cover up the noise). The resonating vibration/oscillation is still there.

I saw somewhere (forum or youtube) where someone designed a new PTO belt tension arm to give the spring more mechanical leverage over the pulley. I hope I can find that again. Anyone have a link?

Edit: It was this thread. sbrilla11, please post the design, or video, or something. Thanks.

Edit2: Also, I don't find myself getting covered in clippings at all, or much on top of my deck. My deck did come delivered with the deck baffles. They are red, not black like the ones in Fueled Iowa's video. If yours did not come with them, maybe they will help?

Edit3: I have been running with the discharge chute down. I took it completely off just now (eliminating as much as I can to reduce rattles). I think I will get a small amount of clippings on me now. I'll report back over the weekend, after I mow again.
Click to expand...

Interesting about the baffle kit. I do have as I had purchased it when I got the mower but with all the issues with the deck I never installed it. I’ll install it to see if that helps. Thanks.

Also, I’m currently researching other zero turns as my deck is starting to vibrate and rattle again. It’s not as bad as it was before but I’m thinking that it will get worse over time as when I got it back from the dealer it didn’t do it at all. Right now I’m looking at John Deere and eXmark. Only thing I don’t like about eXmark is they use their own brand engine until you get into the real high end ones. I’ve always had great luck with Kawasaki.


#77

M

my87csx481

I did notice a minor increase in clippings buildup on the deck, and on myself, running with the discharge chute completely removed....but there was a breeze too. Baffles are still installed. My "lawn" is in pretty rough shape though. Lots of weeds, and tons of dandelions. It's been neglected for many years.

I tried adding a 7/8" diameter bushing over the spring tension bolt. This didn't really do much. So I removed it.

The arm is the same part number for the 3 deck sizes. The 60 uses a different hole for the tension pulley, which gives the spring even less leverage over the belt. I drilled a new hole about an inch closer to the pivot point on the arm, and mounted the pulley there. Still didn't really do much. I'm going to try adding my 7/8" bushing again. And maybe come up with something to increase tension on the spring even more. I may try the 60" hole too....just for the heck of it.

I'm stuck with this one for now. I'll probably sell/trade it next season. Not sure what I'll get. I was trying to not spend 10k on a mower, but still get something decent, and that will last ~10 years (hopefully).


#78

cpurvis

cpurvis

You can always just put in the ear plugs, go mow and ignore the vibration. If it's truly a problem, something will eventually break.


#79

G

gravelyzthd52

Looks like Gravely is finally addressing the problem. Sent this video to my dealer and asked for the same kit. He said he hasn’t seen any bulletins about it but will check it out tomorrow. Hopefully this is a permanent fix because this really is a great machine.

https://youtu.be/xf0lDSKFTgM


#80

M

my87csx481

Thanks so much for sharing.

I think I did hear a little of the ring-a-ring-a-ring in the video....but significantly reduced.

I have a case number with Gravely that I never bothered to pursue with my dealer. Now I will.


#81

M

my87csx481

Contacted my dealer with the case number.

Paraphrasing the dealer's response: They are still working out some issues with the kits. They are not yet available, but will be shortly. They have multiple tests going on already (I offered to be a tester). There will be a service update once the kit is available.

At least they're acknowledging it now. Here's to hoping for even less vibration than in the video with the production kits :drink: :drink:

I had a chance to measure my belt and pulley temps this past weekend with an IR temp gun. 120°F at about 70°F ambient. I am running a bit more belt tension than stock. Hopefully everything survives the vibration until parts are available.


#82

C

Cphillips82

How is it that a couple people were able to get it already? (Based on Shawn Bond’s video and a comment from another guy that said his was on the way).


#83

C

Cphillips82

Have you been able to get this kit yet?


#84

G

gravelyzthd52

Cphillips82 said:
Have you been able to get this kit yet?
Click to expand...

I called Arien's customer support directly and asked about the anti-vibration kit. The first person I spoke with sent me to another person who knew exactly what I was talking about. Without much hassle at all she said they would contact my dealer about sending out the kit. I got a message from my dealer yesterday that he received it and he's actually going to come pick up the mower for me to do the install. It might be a week or two until he's able to do it but I will post updates as soon as it's done.


#85

C

Cphillips82

gravelyzthd52 said:
I called Arien's customer support directly and asked about the anti-vibration kit. The first person I spoke with sent me to another person who knew exactly what I was talking about. Without much hassle at all she said they would contact my dealer about sending out the kit. I got a message from my dealer yesterday that he received it and he's actually going to come pick up the mower for me to do the install. It might be a week or two until he's able to do it but I will post updates as soon as it's done.
Click to expand...

Thanks for that info. I actually just got off the phone with Shawn Bond's dealer who dealt with an 'Andrew' in Gravely's tech department. I'm going to try to get a hold of him, glad you got someone that knew about it. Let me know how it goes with yours :thumbsup:


#86

C

Cphillips82

gravelyzthd52 said:
I called Arien's customer support directly and asked about the anti-vibration kit. The first person I spoke with sent me to another person who knew exactly what I was talking about. Without much hassle at all she said they would contact my dealer about sending out the kit. I got a message from my dealer yesterday that he received it and he's actually going to come pick up the mower for me to do the install. It might be a week or two until he's able to do it but I will post updates as soon as it's done.
Click to expand...

My dealer just called me, Gravely is sending them a "test kit" (assuming thats what theyre calling it since not official yet) which should be here next week and then we'll set up a time to get it installed. Keep you guys posted.


#87

M

my87csx481

Sorry for not replying sooner. I haven't heard anything from my dealer. I was left with: I'm not getting anything until the kit is released (because they had enough people with pre-production/test kits). Interesting that they're still sending out test kits. I guess my dealer doesn't move enough units. (In fairness, the population size and density where I'm at is few and far between).

Glad to hear some people are making progress. Please keep us all posted, and I'll do the same. Thanks.


#88

S

Shafenator

I just purchased a brand new ZTX52 over the weekend and as soon as turned on the blades I noticed this issue. I instantly googled it and low and behold this was at the top of my search. Glad to hear Gravely acknowledged the issue and it sounds like they are working on a solution. I sent my dealer a message and referred this thread. They said they never heard of this issue and were not aware.

I am bringing the machine to them tomorrow for them to take a look. The virbration was driving me nuts!! Felt like a blade was off balance. Other than that the machine seemed to cut fine.


#89

cpurvis

cpurvis

gravelyzthd52 said:
I called Arien's customer support directly and asked about the anti-vibration kit. The first person I spoke with sent me to another person who knew exactly what I was talking about. Without much hassle at all she said they would contact my dealer about sending out the kit. I got a message from my dealer yesterday that he received it and he's actually going to come pick up the mower for me to do the install. It might be a week or two until he's able to do it but I will post updates as soon as it's done.
Click to expand...

And what was the outcome?

Shafenator, don't expect great things to happen quickly. My friend's mower has been at the dealer since last November and he is still waiting, wearing out a brand new 61" loaner mower in the meantime. They offered to let him keep the the 61" mower but he declined because it's a little too big and he also wants the Kawasaki engine (the 61" has a Gravely engine).


#90

S

Shafenator

cpurvis said:
And what was the outcome?

Shafenator, don't expect great things to happen quickly. My friend's mower has been at the dealer since last November and he is still waiting, wearing out a brand new 61" loaner mower in the meantime. They offered to let him keep the the 61" mower but he declined because it's a little too big and he also wants the Kawasaki engine (the 61" has a Gravely engine).
Click to expand...

I just noticed this thread is for the HD model. I have the ZTX52, has anyone you know of reported this issue for the ZTX model?


#91

C

Cphillips82

Kit was installed and I’ll have an update tomorrow after I get it delivered and test it out!


#92

M

my87csx481

Awesome. Please let us know.


#93

cpurvis

cpurvis

Do you have a part number for this kit?


#94

C

Cphillips82

cpurvis said:
Do you have a part number for this kit?
Click to expand...

According to my dealer it is still in the process of testing so there’s no part number.


#95

C

Cphillips82

So first impressions are good and bad. I have the same parts replaced as the person that posted the youtube video with the kit installed. The good news is that there is less belt slop/whip and it seems to dampen vibration in general with the pto engaged. The bad news is that it doesn't seem to make much difference in that rattle noise that whirs in and out. That still seems to be more related to that front left deck arm. I think its still worth having installed to calm down the belt whip but imo Gravely needs to create a fix for that deck arm. I think if they could keep the arm from making contact with the bracket it sits in, that would help a lot. When I have time im going to try and create 2 shims to slide in there and zip tie them around the arm so they stay put and that will keep the arm from sitting against either bracket which seems to be a large part of the noise.


#96

cpurvis

cpurvis

There is something about that deck design which causes it to have a resonant frequency close to its operating rpm. When I first saw it, I thought it was unusual in that you could take off a belt and still have the center and left spindles working. Seems like one too many belts to me and the deck drive belt flops around far too much.

I tried to change the resonant frequency by adding magnetic weights to the idler pulley brackets but either I didn't have enough weights or was putting them in the wrong places.

I've never seen a mower deck with a damper on the idler pulleys but, short of redesigning the deck, (which I think it needs) that may be a good enough band-aid fix.

edit: I don't own one; a friend does. That's how I got mixed up in this.


#97

B

Bullgoose

cpurvis, I just joined the forum today, and was reading about this vibration problem. I have a ZT HD 60, and this thread caught my attention. After reading your post, I am pretty sure that you are on the right track. I worked in the vibration field for 21 years, and learned a few rules of thumb about causes of vibration.. As you pointed out, the deck has its own unique resonant frequency. For whatever reason, the 52" deck has that resonance, and it is inside the machine operating range. That is to say. as the mower ramps up from idle to full speed, at some machine speed the resonance is excited and the vibration starts.

The decks on other machines have a unique resonant frequency as well. Those frequencies are well above the operating range of the mower. Therefore, the deck does not vibrate. I make an assumption here that the operating speed for the 52" mowers is roughly 3600 RPM. This would mean that the deck vibrates because the resonance is right on top of the 3600 RPM (max speed).

A detail that must be respected about vibration is that it can get complex. If you take the 52" deck (alone) and set it on a work bench, the resonance will be unique for that part. As you add components (spindles, pulleys, etc), the resonance moves around because the resonance of each component adds to or subtracts from the original resonance of that deck system. What I am saying here is that the composition of all of the parts attached to the deck affects the resonance. I know I am using the word resonance a lot, but please bear with me.

cpurvis, your idea is on the correct course, but I see two possible "gotchas". 1) As you pointed out, the magnets attached to your weights may not be strong enough. When dampening a system the dampening weight needs to be rigidly attached to have the maximum impact, and 2) You may not have enough weight to resolve the vibration.

I know that I have babbled long enough, so let me cut to the chase. Please remember that I have no data from these components so I am just sharing information in a limited fashion based on my life experiences. If I was trying to solve this, the first thing that I would think about is how to stiffen the deck system.

How do you do that? There are a couple of ways. The first is to make the metal in the deck thicker. This would add rigidity to the structure, and, therefore, suppress the vibration. This is not likely going to be what Gravely does because metal costs money, and they are in the business to keep as much of that as they can.

Another way to raise the resonant frequency is to add rigidity by using a method that can be field implemented. This is the solution I would try to follow first because it can be done in a practical fashion. I would take a length of strap metal like you can buy at building supply stores. For a 52" deck I would suggest maybe 30 to 40 inches in length. I do not know how the deck is constructed on top so you may have to alter the length. Longer is better. You can also add rigidity by using thicker metal. For example, instead of a 1/4" strap maybe try a 1/2" strap. Along the length of the strap drill a hole for a 1/4" bolt every six to eight inches. Drill the holes through the deck and the strap. In each hole place a 1'4" bolt. This will bond the strap to the deck very tightly. Place the bolt heads on the bottom side of the deck to minimize intrusion into the blade area. The strap needs to be on a top flat surface of the deck. Preferably toward the center.

You will have to decide if you want the holes in your deck. The strap will be on top. If you wish to remove it you can do so, and leave the bolts in place.

This is a theoretical solution. The philosophy is the same for any lawn mower. It is just physics. You may have to get creative in your own way. If anyone implements this, please let us know the results. If it does not work, I may have to change my user name.


#98

cpurvis

cpurvis

Thanks, Bullgoose! I'm glad you joined the forum.

I wish Gravely had you working on the problem!


#99

M

my87csx481

@Bullgoose - there are several existing holes/bolts that go through the top of the deck (I think they hold the baffles....I'd have to look again). Would I be wasting my time with 3 10" sections of strapping (in order to use existing holes), instead of 1 30" or 40" section?


#100

B

Bullgoose

my87, as I stated in my post, there is no right or wrong way. What you suggest is worth a try. I know I would prefer to drill my deck as little as possible. If the bolts you wish to use retains the baffles underneath, then by using those existing holes with longer bolts you would save some drilling. Be sure the strap.is flat against the deck. That is to say, leave no gaps between the two parts.

If you use two straps, make them as long as will fit. Reuse the existing holes that you refer to as much as practical. If you go with 10"-12" lengths, place a bolt on each end, and one in the middle. You do not have to use a ruler to space the holes. Just place the holes toward each end, and close to the middle. The most important objective is to have the two parts as tight as possible. Make the straps as thick as you can. I would guess 3/8" thick would do the trick. I believe Home Depot or Lowe's would have what you need. Let us know of your success..


#101

M

my87csx481

I am going to try "something". Just not sure exactly what.

Is this more about mass, or rigidity? You mentioned 3/8" thick....but how wide? 3/8 square?

I was thinking I could get some square tube stock, the stuff that has the holes in it already. Maybe 1" square....but I'll have to check clearance (above, and around). But this will weigh significantly less than a 1 x 3/8 x 40 piece of flat stock (I think).

If I went with the shorter (~10") pieces, what about putting a small piece of plastic, or rubber, in between the brace and the deck (just in the middle of the 10" brace)? To force the brace to flex a bit, and put pressure at the center of the 10" length. Is this worth trying? Before drilling the hole, and putting a third bolt in the middle?

I'm really hesitant to drill more holes in the deck (for now). I really miss having access to welders, and milling machines, and lathes (I used to be a machinist).


#102

T

tbzep

I made my own custom fit earbuds using a custom molded earplug kit and some decent ear buds. I use plain ear muff type hearing protection over them. I don't here the chute rattle. I don't hear belts rattle (they don't, but I wouldn't hear them if they did). I do hear the engine and PTO a little, but I mostly hear my music without having to turn it up, thanks to doubling the hearing protection. I subscribe to the "out of sight, out of mind" and "ignorance is bliss" theories. :thumbsup:


#103

B

Bullgoose

My87, I apologize for not following up on this topic. I have been preoccupied with tractor problems so I have not paid any attention to this thread. I will try to do better. You asked: "Is this more about mass, or rigidity?" My reply is "yes". I apologize for being flippant, but it is truly about the interaction of both influences.

Let's take a hypothetical situation: Remember, there is not one single solution, as we will see by example.

If you put a 30" X 1" X 1/2" solid steel bar on your deck with the 1" being vertical, it may solve the problem even if it only weighs 5 lbs, but it may not. However, you will be more assured of success if the bar weighs 50 lbs. Now, take that same bar, and cut it to 30" X 1/2" x 1/2" and put 100 lbs on it. That may solve the problem as well, but it may not. I know that some of you are saying: "Bullgoose does not know what he is talking about.

I am using extreme examples to show that it is not just one influence or another. As I said in my initial explanation, I do not have the data to analytically measure the frequencies involved, so I just took a reasonable starting place because the materials and the procedure are easy to come by. If the vibration continues, increase one variable or both. Without the data, we are just guessing what the solution is.

As I have written this post, another idea came to mind. I have never done this, but it would stand to reason (to me) that it would work. Take your mower, and power it up to the speed where the vibration occurs. Take a heavy solid weight (maybe a sledgehammer) that can have force applied through the handle to the weight on the head. The sledgehammer definitely has the rigidity because of its' thickness. Take the weight, and set it on the deck at any given spot. If the vibration disappears, you have found a "sweet suppression spot". If it does not go away, press down firmly on the handle (more weight). If no suppression, move to another spot. Try this until you find a point on the deck where the vibration disappears. Remember, when I started this exercise, I assumed that the deck is where the vibration exists. If my idea does not work, then the vibration is generated at some other point on the suspension of the deck.

Try other points on the complete deck assembly inclusive of all contact points they have with the with the deck. This technique should be easy for anyone to try, and it does not cost anything. It sounds to me like the price is about right.

Regards,


#104

M

my87csx481

No problem Bullgoose. Life has a habit of getting in the way from time to time. I will be trying the sledge hammer trick this weekend.

My dealer contacted me this past week. They have the "kit" for me. I will also be picking that up tomorrow (doing the install myself, at my request). I'll report back with kit part numbers, if possible. Supposedly it's two kits.

I have been convinced all along (with no supporting info) that if the belt was not flopping around so wildly, the vibration noise would go away. I have spun all my pulleys looking for wobble/run out. All seemed fine. It occurred to me that maybe the thickness of the belt is irregular, causing the flopping. I'll look at that too, when I dig into this over the weekend. I'll only be able to measure the thickness between the two parallel surfaces of the belt though. I do not have a way of capturing the V and measuring from there to the back of the belt. Or do I? I suppose I could set up a dial indicator on the back of the belt, while running it through a pulley. I'll also report back with whatever I find out.

Thanks again to all that have contributed to this thread, and youtube.


#105

M

my87csx481

2 part numbers. First one is basically new pulleys, new tensioner arms, and new hardware. Second part number is new discharge chute, new bogie Wheels, and new hardware. I have not installed anything yet.

59116500
79108000


#106

M

my87csx481

What a waste of time.

The pulleys and tension arms are dimensionaly the same as the originals. They also weigh the same (within a couple grams of each other), using my kitchen scale. The new pulleys actually had more wobble than the old ones .035-.040" vs .015-.025", as measured with a .0005" dial indicator, on the surfaces the belts ride on, with the pulleys bolted to the shafts they drive. I have a mag base that I stuck to the deck's top surface to hold the indicator.

Measuring the belt thickness of the parallel belt surfaces with a dial caliper, I got between .395 and .420"....but most times, it was .400" (measurements taken every couple inches).

Basically, the spring anchor for the smaller tension arm gets a new bolt, with fuel hose on it, instead of the metal bushing. The bogie wheels get new, larger diameter bolts, with no metal sleeves, and no spring washers. The discharge shoot mounting bracket gets a couple holes drilled through it and the deck, and a couple bolts through the holes.

Perhaps a physics major, or a hardcore mechanical engineer could take the time to explain to me how swapping pulleys and arms of the same dimensions and masses will alter the violent belt vibration? I fail to see how these parts will do anything other than suppress the rattles somewhat. In my case, I've already removed all the guards, chute and bracket....months ago. So I didn't bother installing any of the kit. I'm not sure how I will proceed with this. I am extremely disappointed.

I did try probing the deck with an 8 pound sledge hammer. I could not find a sweet spot. I went as far as standing on the deck (I'm a big guy at 230 pounds). That helped a little, when standing on the left side. I also noticed that the top surface of the deck does vibrate with the oscillation of the belt vibration. I will be adding stiffeners at some point, and I will explore adding another pulley inbetween the PTO and the first pulley (on the left side of the machine....the slack side of the belt).

pasted.jpg


#107

cpurvis

cpurvis

I recommend you do some before and after kit installation videos. I know it seems like a waste of time, but I'd install every new component of their kit and if it makes no difference, you'll have video evidence of it.

Let's hear what Bullgoose has to say about it.


#108

N

Newcombe

Hi Guys, just to chime in on this thread as I'm contemplating buying a ZT HD 52" in the next couple of weeks. I'm now having second thoughts. I do like the Gravely machine compared to other brands for the money. At this point should I buy the 48" rather than the 52 due to this one sole issue, the 60" would be too big for where I keep it? Any help would be appreciated before I make a $5,000 mistake.


#109

cpurvis

cpurvis

Try the 52" you intend to buy (the exact unit). If it vibrates, take it back. If it doesn't, buy it but with the understanding in writing that if it starts to vibrate, you want a whole new deck.

If they won't take that deal, pass it up.


#110

N

Newcombe

It surely makes me nervous to make the purchase seeing all the issues these fine folks have had with their units. Would the dealer be able to make that decision on replacement of the deck prior to Gravely's approval?


#111

M

my87csx481

My advice: do not buy without first trying it out. Fire it up, engage the blades. Make sure the noise is not objectionable to you. For some, ignorance and ear plugs are enough to achieve mechanical bliss. For others, that have seen smooth running belt drives (on motor vehicles and other machinery), it's painful to watch and listen to. The blade drive belt on mine has vibrated wildly from the first time I fired it up.

Update on the kit: part of the procedure involves installing washers (as shims) under all the idler pulleys. Then perform a belt alignment. I installed the washers exactly as described in the instructions (one flat washer under each pulley). This has raised the idlers high enough that the bottom lip of the pulley is contacting the belt/s (too much, in my opinion). But fired it up anyway. It seems to have helped at high speed. At idle, forget it. Much worse. But who runs their blades at idle?

As I mentioned, the contact amount is probably too much, and it is deflecting the belts axially. I am going to try to find thin flat washers to use as shims....to split the difference in hopes of a little axial contact will still dampen the harmonics.

Not a fix, in my opinion. My belts were not misaligned to begin with.

The instructions do not mention it but, I would think that you would want to adjust belt alignment with the deck at the height you use it at. And if you use it at extreme different heights, I guess use the middle position between the two, or where ever you use it most. I think deck height affects where the belt rides on the stationary idler pulley.

I need to try to find a replacement drive belt. Something kevlar reinforced. Maybe that will settle it down even more?


#112

cpurvis

cpurvis

Newcombe said:
It surely makes me nervous to make the purchase seeing all the issues these fine folks have had with their units. Would the dealer be able to make that decision on replacement of the deck prior to Gravely's approval?
Click to expand...
Only way to find out is to make the offer.


#113

N

Newcombe

I will be contacting the dealer later this week and will make that offer. My87, I will engage the belts before purchasing for sure to check. You seem determined to fix this issue and I have confidence you will.
Did anybody's machine seem to get worse once things started to wear in to where everything is not as tight?


#114

M

my87csx481

I haven't noticed anything getting worse.

If anything, things have gotten better (but I've made some minor mods along the way to make it better).

I've got about 35 or 38 hours on mine right now (can't remember.....maybe it's 35.8).


#115

M

my87csx481

Aftermarket kevlar belt on the way. Not putting too much hope into this....but need to try it for my own sanity.

Kit update: The washers/shims in the kit are .075" thick. My pulleys were NOT out of alignment before the kit. But based on the .075" shims putting some axial pressure on the belt....I now have one .045" shim under the stationary idler pulley. Nothing under the other two pulleys. It's a little better than before the kit.

But the kits just attempt to "fix" the things that rattle. IMO, it's the belt's harmonics that are causing all the other parts to rattle. The "kits" do nothing to address the belt's harmonics.

IMO, Gravely should just supply washers for shims, and the discharge chute kit (which includes bolts and new bogie wheels). Not sure why they're sending new pulleys and arms. Seems rather expensive. The pulleys do nothing, nor do the arms....in they're current/identical-to-original configuration anyway.

Oh yeah, I still have my extra bushing on the large idler spring anchor too....to give it a bit more tension.

The saga continues....:confused2:


#116

cpurvis

cpurvis

I noticed the drive belt whipping all over the place, too. It's kind of a weird arrangement in that the drive belt powers the center and left blades and a second belt connects the right blade to the center. We took the belt off the right spindle to see if that made a difference and on that mower, it did not. Going from memory here because it was last November that we did this. It went back to the Gravely dealer that week and has not been seen since.


#117

N

Newcombe

cpurvis said:
I noticed the drive belt whipping all over the place, too. It's kind of a weird arrangement in that the drive belt powers the center and left blades and a second belt connects the right blade to the center. We took the belt off the right spindle to see if that made a difference and on that mower, it did not. Going from memory here because it was last November that we did this. It went back to the Gravely dealer that week and has not been seen since.
Click to expand...

So Im happy to say that I picked up my new ZTHD52 yesterday and thankfully it does not have the dreaded vibration. My87, how did you make out with your aftermarket Kevlar belt, did it make any difference?


#118

cpurvis

cpurvis

My friend was given a brand-new 60" Gravely loaner. He put about 60 hours on it and was offered it as a replacement but the 60" width just barely fit on his trailer and he didn't like the 'Gravely' brand engine.

Then they gave him a brand-new 52" replacement. He's put about 15 hours on it, says it has the same deck vibration problem as the original. I mowed with it for a few minutes and it seemed to me the noise was coming from the discharge chute. We took the discharge chute off and a huge amount of the noise went away.

Removing the discharge chute did not SOLVE the vibration problem. I can still feel it; he can't. It's cyclical in nature and anything 'loose' on the deck, such as the discharge chute was in this case, will rattle.


#119

W

Woody99

I have a 52" that's making the vibration too. It's done it since day one.
Sometimes, it's perfectly quiet, but other times it just rattles really bad. It sure seems to be harmonic issues, and the dealer is working with the factory on it. We'll see how that works out.

Reason for the post is to ask a question or two.

I'm running aftermarket high lift and mulching blades. I've never had the factory blades on it, and wondering if the heavy aftermarket blades make a difference, adding to the problem?
Are most of you running stock blades?

Also, on the first set of blades (high lift) I had to balance them to perfection in order to keep from shaking things too much. They weren't off too much, but a good balance helped a little.

Something that I did, and would like to see if it helps anyone else, is I loosened the blades and moved them a quarter turn or so. It feels like it changed the harmonic point and reduced the vibrations to nearly an acceptable level.
I swapped those blades for a set of mulching blades, and the vibrations returned. I haven't tried yet rotating the blades because I don't think this is a real "fix" and want the dealer to hear and feel how much it shakes at times.

Another thing I found is some paint had been rubbed off on the bottom back side of the foot rest plate. There's a big bar that goes across the back, and on both the left and right sides the metal was bare. I put a couple of strips of heavy velcro on one side as a pad. It stopped the rubbing, but didn't do much for the noise.

Anyway, just sharing my experience and a couple of thoughts.


#120

M

my87csx481

I didn't get notifications of the new activity (even though I signed in since the last notification).

The kevlar belts worked beautifully, for the first 5 or 10 minutes. Almost no belt vibration. I have about 5 or 6 hours on them now. Same old ring a ring a ring. Next step for me is figure out how to mount an additional idler pulley half way between the PTO and the deck (with pressure on the slack side only).

I am running the stock blades for the ZT HD, and also run a set of stock blades from a Pro-Turn 200/400. The 52" 200 has identical spindles to the 52" ZT HD. The Pro-Turn blades are a little bit thicker, and a little bit wider....so slightly more mass. All my blades are balanced using a Magna-Matic 1000 since before they ever touched grass. I found that the virgin blades were really close to balanced. Very suprised. Swapping blades between the two sets does nothing for my vibration.


#121

W

Woody99

I wish I could put my finger on the rattle/noise/harmonics and what's causing it. Some days, the harmonics are not bad, but at some point during my mowing session, it starts and shakes things up. It certainly does depend on the engine load/rpm. When even slightly loaded, the rpm must drop enough to stop the harmonics, at least in my case. If I'm coasting down a slight incline, the harmonics start again which induces the rattling.

I can't recall if I read much about it here, but has anyone tried running motor at ~30% with the blades engaged? Mine shakes BAD, and there is really no reason for it to do so. I wouldn't mow like that, but it shouldn't shake so bad the fenders are moving. At that slow speed the vibration is what I would consider at a frequency that one of the pulleys would be rotating. Not like a knot in the belt going around, but everytime the pulley makes a rotation. That could easily translate to the harmonics observed at full power.

More of us should contact the factory and let them know about this. When I called they said they had very few reports, which percentage wise may be true, so let them know if you haven't.

My new parts are supposed to be installed soon, so hope that provides a resolution.


#122

M

my87csx481

Mine sort of does the same thing. It will stop vibrating sometimes, under heavier blade load (taller, lusher sections). But it comes right back. I have not noticed incline effects, but I wasn't paying attention to notice. I have been trying to psychologically suppress the noise:laughing:

I also see different amounts of belt movement at different rpm's. Try it at idle. On mine, the fenders look like they're about to shake themselves off the machine. 50% is almost as bad.
This is with both types of belts.

Edit: *both types of belts, and both types of blades (ZT HD and Pro-Turn 400).


#123

M

my87csx481

Off topic (sorry).....

If you had the opportunity to replace your vibrating ZT HD, what would you be looking at? John Deere, ExMark, Toro, Kubota, Husqvarna, maybe a Pro-Turn? Must be Kawi. I'm done with Briggs and Kohler....if I can help it, and given the choice.

Please start a different thread with this question. Don't want this topic getting derailed.--Mod

Sorry, new topic started here (hopefully it's in the correct place): https://www.lawnmowerforum.com/showthread.php/57025-Zero-turn-suggestions-(to-replace-Gravely-ZT-HD)?p=344414#post344414


#124

C

countryboy89

I purchased a Ariens Apex 48" new. It has single digit hours on the hour meter now. The deck belt wobbles, thrashes creating a vibration that can be felt while mower is in operation. I noticed this the first time I used it. Returned to dealer. He brought out a Ariens Apex 60", brand new machine. Started it up, turned on the blades. That deck belt doing the exact same thing. Thrashing around creating vibration. Dealer told me it is normal operation. I told him I strongly disagree, and this is going to cause premature belt wear and bearing failure, spring failure. Dealer said they have had no other complaints on this. He told me that the engineers considered this when making the machine. I told him there is a problem, and needs to be corrected. I contacted Ariens directly after getting home that day and explained situation to them. They talked to the dealer to see what dealer assessment was with my machine. Dealer told them it was running normal. Ariens did get back to me saying that it is normal, and if you have any concerns to get back to them. I'm sorry but "normal" here is not right. Just because it come from the factory that way doesn't mean its going to be ok. Belts are not covered by warranty, and the consumer is getting hung because of failure to address this problem. Pretty obvious here after reading this post, there is a definate problem that needs attention with these machines. These companies instead choose to turn their back on hard working consumers that put confidence in their product and purchased it. They are failing to act because it will cost them money. Instead they pass the cost to us. This is so wrong......


#125

cpurvis

cpurvis

I don't think there is anything inherently wrong with the deck/belt design. My friend that had the problem on his new ZT52HD, once we removed the chute, he's happy with it. The vibration is still there; there just isn't anything loose for the vibration to make rattle. I've mowed with it and it does a beautiful job. I personally, would not give up on Gravely.

This is his 2nd ZT52HD. His old one never had the vibration/rattle and I will bet that if we could compare the old to the new, the deck/belt design would appear to be identical.


#126

W

Woody99

The dealer put on the "kit" recommended by the factory. I can't say it helped anything, and maybe even made it a little worse.

I'm going to reposition the blades a little bit and see if it helps like it did once before.

Seems like the problem is recognized, but not being resolved. :(

Don't get me wrong, I like the cut of the mower, and everything else about it, other than that darn harmonic vibration. Boo...


#127

M

my87csx481

@countryboy89: the dealer told me mine was normal too.:rolleyes: I've owned many motor vehicles, lawn tractors, and used many machine tools. I have never seen a v-belt, or serpentine belt behave like this, under normal circumstances. This is my first zero turn, so maybe it is normal for this application:laughing:

To be fair, I really do like my mower....a lot, and the cut quality has been great. If only the ring a ring a ring a ring would stop.

Seriously considering an Exmark Radius X. Going to demo a Radius S tomorrow.


#128

C

countryboy89

I feel this is not normal for the deck belts to dance and wobble like they do on this Apex I have. Whoever designed this machine perhaps was not on top of his game. I doubt that these mower makers have top engineers designing these units. Top guys are too expensive. What's really disappointing is that they go ahead and market these mowers the way they are.
And how many consumers will notice? How many will complain? It's a game for them, and they win. Odds are most will not take note. And when the dealer and maker says its normal, what can we as consumers do? My dealer told me they have had no complaints about this belt issue. He's a large dealer, sells many mowers each year.
What would you think if you opened the hood of your new car or truck with 20 miles on it and saw the belt dancing, wobbling like it does on these mower decks? Then, the dealer said that's normal. Just because this is a lawn mower doesn't mean it shouldn't be made to perform properly.
My question is to anyone who is reading this thread to tell us if they know anyone who owns or has owned a Gravely or Ariens for several years with this issue. What has been the history of belt replacement, bearing replacement on the deck with that machine? How many hours on the machine before a belt or bearing failed? This Apex I purchased is a commercial unit. It's made to mow bunches each summer. I live on a acreage and mow a little over an hour each time. Light use for this type of machine. But, I wanted a quality machine. I am very happy with the cut. Lawn looks great after I get done.
I plan on looking at other machines to see if their deck belt dances, and wobbles like these do. The solution could be something as simple as spring tension. If we all would have tried our machines out at home, then told the dealers to fix this issue or I am not interested in this mower....it would have been resolved. Funny when something is paid in full, they don't want to be as helpful anymore.


#129

W

Woody99

Seems like part of the issue is the dealers are telling the factory that the mowers are operating normally, so not much more being done to resolve the root cause that generates the harmonics causing the vibrations. I think most of the parts installed were to tighten things up so the vibrations didn't cause them to rattle, rather than getting to the reason for the vibrations to start with.

My dealer keeps telling me it's normal, and all mowers do it, even different brands. We all know that's not right.

As I mentioned before, the "kit" did nothing for me, and now I think one of the replacement anti scalp rollers screeches going over a high spot. :(

Also, I tried repositioning two of the three blades by loosening the mounting bolt and rotated the blade approx. 90 degrees. That helped more than anything that's been done so far, and reproduces the vibration reduction that happened when I did it a while back with a set of high lift blades.
Give it a try and see if you have the same results.

A side note too, my dealer said to engage/disengage the pto at reduced throttle to save wear on the clutch, and that the clutch would wear out quickly if I didn't. He went on to say that's not covered under the warranty, which I would think is not correct.
He kind of changed his tune a little bit and said to idle down when disengaging the pto so the brake didn't have to work so hard to stop the blades.
It might be my imagination, but since I've started turning on the pto with the motor at full throttle, some of the vibs went down. Maybe the clutch plates need to wear in a little bit, I don't know.

There's something metallic that's still rattling a little bit, that if I could find that I would probably be OK with the situation now that I rotated the blades and turn the deck on at higher rpm.


#130

G

gravelyzthd52

My dealer installed the kit on my ZTHD52 and told me today that it didn’t stop the rattle or vibrations. He’s been in touch with Gravely to let them know and has sent them videos. He’s waiting to hear back.

At this point it seems like they should either offer a refund, replacement, or maybe even a credit for the cost of the machine towards an upgrade at a discount. I’m going to call them tomorrow. It’s been a year and a half now since I’ve been dealing with this and I’m out of patience. My dealer has gone above and beyond but Gravely needs to step up and make it right.


#131

N

NealS

I have been wondering? My kubota tractor has a non adjustable idler pulley, set just behind and near the middle of the long air conditioner compressor belt. Since it is non adjustable, I presume it is to keep the belt from slapping back and forth. Do you think it might be possible, the slapping we can see our mower belt doing sometimes, might be causing this rattle, and maybe we could do similar with a back side idler on our mowers long belt?


#132

N

NealS

Well, we put an idler pulley on the back side of the long side of the drive belt today. Mounted it to push in on the belt about 1/2".
First impression was it made a world of difference in how quite it was.
We only mowed about 1/2 acre so far and before we were done, I heard a little rattle :frown: at times.
After installing and running at fast idle, the belt would still whip (maybe not as bad) between the idler and the front pulley. At the same time the tension pulley would be jumping a lot. Then we went to full throttle and everything smoothed out. That was without a cutting load of course. I guess time will tell.

Someone else was asking about blades. We ran the factory blades for the first year, then changed to the heavier Oregon G6 Gator Mulching blades. We could tell no difference between the two, other than it mulches better.


#133

cpurvis

cpurvis

Are all of these ZT52HD's powered by the same engine? If not, is the vibration common to all, or just the Kawasaki?

I had originally scratched off the engine as being a possible cause but what if Kawasaki changed the flywheel slightly?


#134

W

Woody99

cpurvis said:
Are all of these ZT52HD's powered by the same engine? If not, is the vibration common to all, or just the Kawasaki?

I had originally scratched off the engine as being a possible cause but what if Kawasaki changed the flywheel slightly?
Click to expand...

Mine has the Kohler motor.

I probably buried my thought to far in my comments, but two times I have been able to make significant reduction in the deck rattling by repositioning two blades. Could a couple of you try it too and see what happens?
I don't know why it would make a difference, but it has. You would think that the installation of the blades would put them in a totally random position relative to each other, but loosening two and moving them a quarter turn really seems to make a difference.


#135

N

NealS

Well, we found that we still had the metal to metal noise under some mowing situations. Saw a youtube video where the owner was putting rubber grommets on a bolt head to keep it from touching the left side belt guard. Pulled our belt guard and found the same bolt head had worn the paint off the underside of the belt guard.
We did our fix a little different.
Took a 1" socket and set it in the press. Placed the belt guard (upside down) over the socket with it lined up on the scrubbed paint marks, then put a small socket over the paint marks and proceeded to apply pressure to the small socket until it had formed a raised place in the belt guard, directly over the bolt head it had been hitting.
This seems to have stopped the metal to metal rattle.
First pic, cover is upside down laying next to the bolt that it had been hitting and before our press work. 2nd pic is after press work. 3rd pic is with belt guard installed.

Attachments









#136

W

Woody99

Regarding the bolt head clearance, I'm not sure if mine came from the factory or was modded by the dealer, but I have about 3/8' clearance above the bolt to the guard.
The guard has a nut below it at the mounting points, and then a nut above it to secure it. There are rubber bumpers on the piece where you can step to hold it up too.

20191001_153539045_iOS.jpg


#137

N

NealS

I think mine is mounted similarly. Possibly the factory upgrade for this problem may have been taller sides on the belt guard. Just thought if someone had this problem and a press, it might be easier to fix than carry back to dealer. Seems like a waste to make a repair by getting and installing a new guard, when it is so simple to fix if you have a press.

I did think later though, it might be better to use larger sockets, so you would not have to be as accurate with the location of the raised area.


#138

M

my87csx481

Mine is a Kawasaki.

My belt guards do not interfere with anything but, I completely removed them a long time ago, to rule them out as a source (along all the discharge chute and bracket and hardware).

I strongly suspect that the whipping belt is causing the PTO clutch to rattle against the "drive dog" that holds the stationary portion in place....possibly being the source of my remaining metal clanging noise....but I'm done screwing with mine....so I will not be validating my suspicion. I've spent way too much of my time reverse engineering, and re-engineering something that is either defective designs, or defective manufacturing processes....or both.

I also strongly suspect that the sheaves of all the pulleys are uneven. Squeezing the belts more in some spots, and releasing the belts more in other spots....causing the belts to ride higher and lower in the pulleys....again, I'm done screwing with mine. I did put a dial indicator on my pulleys, and they did have a bit of a wobble to them (.040" being the worst one), BUT it was only on one side of the V, not both sides at the same time.


#139

D

DRG ZT HD 52

NealS said:
Well, we put an idler pulley on the back side of the long side of the drive belt today. Mounted it to push in on the belt about 1/2".
First impression was it made a world of difference in how quite it was.
We only mowed about 1/2 acre so far and before we were done, I heard a little rattle :frown: at times.
After installing and running at fast idle, the belt would still whip (maybe not as bad) between the idler and the front pulley. At the same time the tension pulley would be jumping a lot. Then we went to full throttle and everything smoothed out. That was without a cutting load of course. I guess time will tell.

Someone else was asking about blades. We ran the factory blades for the first year, then changed to the heavier Oregon G6 Gator Mulching blades. We could tell no difference between the two, other than it mulches better.
Click to expand...

Where did you place the Pulley & where did you get it? a picture would be nice.


#140

H

handtools

countryboy89 said:
I feel this is not normal for the deck belts to dance and wobble like they do on this Apex I have. Whoever designed this machine perhaps was not on top of his game. I doubt that these mower makers have top engineers designing these units. Top guys are too expensive. What's really disappointing is that they go ahead and market these mowers the way they are.
And how many consumers will notice? How many will complain? It's a game for them, and they win. Odds are most will not take note. And when the dealer and maker says its normal, what can we as consumers do? My dealer told me they have had no complaints about this belt issue. He's a large dealer, sells many mowers each year.
What would you think if you opened the hood of your new car or truck with 20 miles on it and saw the belt dancing, wobbling like it does on these mower decks? Then, the dealer said that's normal. Just because this is a lawn mower doesn't mean it shouldn't be made to perform properly.
My question is to anyone who is reading this thread to tell us if they know anyone who owns or has owned a Gravely or Ariens for several years with this issue. What has been the history of belt replacement, bearing replacement on the deck with that machine? How many hours on the machine before a belt or bearing failed? This Apex I purchased is a commercial unit. It's made to mow bunches each summer. I live on a acreage and mow a little over an hour each time. Light use for this type of machine. But, I wanted a quality machine. I am very happy with the cut. Lawn looks great after I get done.
I plan on looking at other machines to see if their deck belt dances, and wobbles like these do. The solution could be something as simple as spring tension. If we all would have tried our machines out at home, then told the dealers to fix this issue or I am not interested in this mower....it would have been resolved. Funny when something is paid in full, they don't want to be as helpful anymore.
Click to expand...




I've been mowing with my Ariens Apex with the 60" deck for a little over 2 years and 155 hrs. I haven't had a belt, pulley or spindle problem yet. I also have what I consider to be an excessive amount of noise and vibration from the deck, but it mows great!


#141

W

Woody99

Another data point:

I mowed the other day, and set the deck down another quarter inch to 3.5". There was little to no noise or resonance. I'm not saying it's gone 100%, but it was a marked improvement from what it had been.

Reminder, the dealer installed the "kit" from the factory. It helped a little, but still had harmonics and resulting vibrations.
I repositioned the blades and as once before, moving the blades helped significantly.
When the dealer returned the mower after the kit was installed, I noticed they had it set to 3.25, which is lower than I normally mow, so I sat it up the 3.75 and never tried it at the lower setting.
Now it makes me wonder if the kit and adjustments were optimized for 3.25? Could be.

Anyway, kit installed, blades repositioned and set to 3.5 cut, the deck is really pretty quiet. Quiet enough that if it would have been like this from the beginning, I wouldn't have thought twice about it.
One more bit of information, the temperature dropped into the 70's from the 90's on the last mow too.


#142

D

DRG ZT HD 52

Woody99 said:
Another data point:

I mowed the other day, and set the deck down another quarter inch to 3.5". There was little to no noise or resonance. I'm not saying it's gone 100%, but it was a marked improvement from what it had been.

Reminder, the dealer installed the "kit" from the factory. It helped a little, but still had harmonics and resulting vibrations.
I repositioned the blades and as once before, moving the blades helped significantly.
When the dealer returned the mower after the kit was installed, I noticed they had it set to 3.25, which is lower than I normally mow, so I sat it up the 3.75 and never tried it at the lower setting.
Now it makes me wonder if the kit and adjustments were optimized for 3.25? Could be.

Anyway, kit installed, blades repositioned and set to 3.5 cut, the deck is really pretty quiet. Quiet enough that if it would have been like this from the beginning, I wouldn't have thought twice about it.
One more bit of information, the temperature dropped into the 70's from the 90's on the last mow too.
Click to expand...
Could you post a Picture of how you positioned the Blades.


#143

W

Woody99

DRG ZT HD 52 said:
Could you post a Picture of how you positioned the Blades.
Click to expand...

I just loosened the bolt on two of the blades, and rotated them ~90 degrees.
It doesn't really make sense to me why moving the blades makes any difference, but it has on the two separate occasions that I've done it.You would think that the initial install location would be totally random anyway.


#144

M

my87csx481

I'll have to try it at a lower height, next time I mow (I might have one last cut for this season). I've kept mine at 4" from day one. When installing the kits, I set the pulley alignment with the deck at the 4" height.

When the machine was brand new, I set the 4" pin height with 4" blocks under the front blade edges, with taller blocks under the back edges to achieve the pitch described in the manual.


#145

M

my87csx481

Dealer offered me a full refund. I took it.

I'll be purchasing something else in the spring. Most likely an Exmark (due to what's available within an hour's drive). Scag dealer is just too far away.


#146

M

my87csx481

I have a couple Kawasaki air filters, and a couple kevlar belts that I posted for sale here: https://www.lawnmowerforum.com/showthread.php/57560-FS-BNIB-Kawasaki-air-filters-4-hours-used-kevlar-belts-for-Gravely-ZT-HD-52?p=347400#post347400

The filters fit FR and FS engines. The belts fit the ZT HD 52" deck.


#147

M

MJS10814

Brand new to this forum. I have the exact same issues with my ZT. Did I miss a antivibration kit number? At Large did it resolve the issue or not


#148

W

Woody99

MJS10814 said:
Brand new to this forum. I have the exact same issues with my ZT. Did I miss a antivibration kit number? At Large did it resolve the issue or not
Click to expand...
www.lawnmowerforum.com

ZT52HD DECK VIBRATION FIX

Another data point: I mowed the other day, and set the deck down another quarter inch to 3.5". There was little to no noise or resonance. I'm not saying it's gone 100%, but it was a marked improvement from what it had been. Reminder, the dealer installed the "kit" from the factory. It helped...
www.lawnmowerforum.com www.lawnmowerforum.com

This is what I found after the kit was installed, and it has been pretty good since then. Cold now, so no more mowing.
One thing I heard from the dealer is that the Gravely Tech Reps ask him if HE thought the problem was resolved. Issue is that he never thought that there was a problem to begin with, so the techs don't have the full story for their data.


#149

A

ariens apex 52

Hello all. I have been following this thread for a few months, looking for ideas to help fix my Ariens Apex 52 (Gravely ZTHD52) which developed a horrendous rattle and vibration soon after purchase. Originally, I had planned to replace the tensioner spring with a fence turnbuckle to prevent the vibration which I believed to be caused by the spring, but I soon realized that when lifted and lowered the tensioner spring stretches too much for this to work. After some deliberation I tried removing the spring and stretching a bicycle tyre innertube over the spring to add resistance, like a car shock absorber, to hopefully reduce its vibration. This worked a little when tested but it seemed the rattle was still as bad as ever, even though the vibration had been reduced slightly. I studied the belt tracking and realized that the way the belt is routed, whenever the deck comes under any load the engine tries to pull the deck towards the back of the machine. The deck is mounted by four arms that would allow the deck to "swing" back and forth. To prevent this, they have installed two diagonal arms from the front of the deck to the frame. On the deck end of these arms there is a castellated nut threaded onto the arm which fixes through a mounting pin on the deck, this has a split pin through the nut to prevent it backing off. On my machine this nut hadn’t been tightened up all the way and the split pin had been installed leaving a gap, this was allowing the deck to move back and forth about a 1/4" so whenever the deck was running it shuddered back and forth. I tightened this nut up and reinstalled the split pin through the next hole and it was instantly noticeable that the deck felt much more solid even before starting the machine. During testing I found that the vibration has been reduced significantly and although there are still a few rattles from places like the belt access panel, the deck runs much more smoothly and seems to cut better. I hope this helps some of you to improve your machines, it has made a huge difference to mine. Perhaps you may want to give it a try. Good luck…cut-quality-gravely-adjust-pitch.jpg


#150

B

bertsmobile1

Thanks for posting.

In reality & good engineering practice that should be rubber mounted to damp out the vibrations.
I have noticed things like this when servicing bigger ZTRs.
I have a few Great Danes & their stabilizer bars have a rubber bush in the pivot end.
When new there is next to no deck vibrations or rattles but when work they make a hell of a racket.
The replacements were solid and they caused a lot of noise & belt dismounting so I got the old ones rebushed and they are back to new.
Decks will vibrate , they have no choice because it has 3 rotating blades and spindles which are not dynamically balance .
Plus the belt has a joint in it and every spring has a resonant frequency


#151

W

Woody99

After reading your post, I checked mine, and it seems pretty snug already. I did have mine in the shop for the vibration and it's very possible that part of their "fix" was to tighten these. On one side, it looks like the nut may have been rotated a notch, but I can't see the other one well enough to see if there is anything has been moved to a different slot.
It's been a few months since usage, but we'll see if the alterations made last fall still work this spring.


#152

R

Rivets

Because if you would read the thread you would see that a member with a similar problem came back with a comment on his original posting.


#153

C

Cphillips82

Just mowed for the first time since last November. Before cutting today I took my blades off, gave them a nice edge and put them back on. There was as little vibration or rattle today as I’ve ever had with this machine, actually there was none. I’m not totally sure if its the way I aligned the blades but nothing else has changed since the fall but it was a pleasant surprise and a great first mow of the season.


#154

W

Woody99

I'd say mine's doing ok so far this season. Like I mentioned before, the dealer put whatever the factory recommended on. At first it was just marginally better, but after moving the blades, it's not so bad now. There is some type of "chirp" that I didn't hear before, but maybe I couldn't hear it over the rattle previously.
I haven't sharpened the blades yet this spring, but when I do, I'm going to see if the rattle comes back.


#155

G

gravelyzthd52

I’m happy to say that so far may deck rattle is 99.9% gone.

I’ve worked with my dealer and directly with Gravely for over two years to resolve this problem and both have been great.

Over the course of this time the deck and all mounting hardware have been completely replaced on my mower (including the deck shell). This includes having the anti-vibration kit installed and new blades.

Nothing resolved the problem until recently my dealer mentioned that the only thing that had not been completely replaced on the deck were the spindles. After replacing the spindles the rattle is now gone except for every once and while I will hear it very lightly, to the point of if it had never been as bad as it was you would never notice it.

It’s great to enjoy mowing again with no rattle noises and fingers crossed that the rattle doesn’t come back. I don’t think it will but at least if it does I know it’s the spindles.

if you’re still having this problem either call Arien’s customer support directly or contact your dealer about replacing your spindles.


#156

W

Woody99

Mine is much better now too, and I have to say the dealer and Gravely tech support have all be very helpful. After the kit was installed, and a couple more things done by the dealer, the noise from the deck isn't obtrusive like it had been.
One factor that seemed to have helped too is removing the big heavy Gator mulching blades. They are well balanced, but I think added to the vibrations. I put factory mulching blades on, and removed the discharge chute blocker, and it's working well.
Gravely was nice enough to add another year warranty to the mower too. Good folks.


#157

dcgou

dcgou

My left side deck vibration was resolved by removing the small cover and placing a rubber grommet over the metal screw that was vibrating against the cover. 100% resolution.


#158

W

Woody99

If you know anyone looking for a discharge chute blocker, let me know.

79210300 Operator Controlled Chute Kit and 3 Gator Mulching Blades


#159

C

coder

I wonder how well the "factory new" blades are balanced? We assume that they are near perfect. I have deck rattle and vibration on my brand new Apex 52. Have not really analyzed yet.
but it is very noticeable compared to my 20 years old Scotts tractor, which run smooth as butter.
I have a power bagger on mine, I assumed it was that... I have a super-duper ball bearing based blade balance checker,
will take off an balance all the blades first and see what happens...

I have just a a couple of hours on the mower. I notice the deck drive belt is dancing/whipping around a bit on the left side of the PTO.
I have only seen something like this in situations when a belt is too loose. I had a very similar problem on my Scotts powerflow bagger drive belt.
The local tractor place had a series of Kevlar belts in various lengths. I just replaced the belt with another, 2" shorter, and the problem
instantly went away. Maybe a shorter belt here may also help? Given the tensioning pulley, it would just not push into the shorter belt quite as deep, and the belt tension
would be a bit tighter. I would trade that for the current vibration.

The right side that is being pulled by the PTO is nice and tight, but the left side seems loose as it is coming off of the PTO.
My impression is that the belt tensioning pulley simply does not tension the belt enough. Unfortunately I do not see any adjustability of the belt tensioner. A heavier spring, or mounting the
tensioning pulley at a different position on the tensioning arm?

Some people in this thread mention a Deck anti-vibration kit. Any more info on this? If I call my dealer, I have to pay them $40 to pick up the mower to look at it, and I anticipate they will
just tell me "they are all like that, its fine" . So I am thinking of contacting Ariens/Gravely first, see if they are willing to send me the anti vibration update whatever that may be.
Thoughts? What is the best strategy attacking this ?


#160

B

bullet bob

Doesn't cost you $40 to CALL your dealer....


#161

cpurvis

cpurvis

If you call Ariens/Gravely first, I suspect they're going to ask if you've talked to your dealer.

So you might as well talk to the dealer first.


#162

C

coder

Does anybody have the belt tension spec for the Apex 52 ( same as HD 52) PTO belt? Is it something like 1/2" deflection @12 lbs pressure perpendicular to the belt?
It would be even better if they had different tensioner springs to swap out to adjust the tension. My feeling is that the belt is simply not
tensioned correctly.


#163

B

bullet bob

Coder. With all due respect sir, I think you need to have a nice long talk with your dealer. This should be your first step.....


#164

C

coder

sbrilla11 said:
Guys, after going to 2 dealers last fall and finding no solution for the deck vibrations (harmonics) I finally got my 52 HD out and decided to fix it on my own. After looking over it was obvious it was related to the tensioner. If you look at the way the arm was designed the pivot point gives the idler pulley twice as much mechanical advantage over the spring. I ended up machining a new arm with pivot point that is twice distance giving the spring the mechanical advantage. The vibrations are about the same however the horrible noise is now gone! The spring vibrates half as much as it used to. If you guys are interested I can post a picture of what I did.
Click to expand...
Effectively, by replacing the tensioner arm with one with a different mechanical advantage, you have just increased the tension on the belt, right?
Was there a calculation involved to estimate the amount of tension increase or did you just eyeball it? Or maybe you have a belt tension gauge, and you used it to dial in the optimum belt tension?
IMHO the same effect could be achieved by increasing the tension some other way.

For example, the easiest and most obvious way would be replacing the belt with a slightly shorter belt. I have successfully done this on my old JD powerflow drive belt, where I had a similar issue. Of course the belt there was way too loose and floppy.

The current Ariens PTO belt is nominal 98.5", and other aftermarket belts are available in 98, 97, or 96" lengths. Actually, my local tractor supply house carries various sizes, so I could go through a few, measuring the resulting tension, until I experimentally determine where I need to be. Probably pick up a few different sizes, until I get to the tension I want and just return the ones I did not need.

Effectively the tensioner pulley/arm just would not push quite as deep into the belt, and the spring would be stretched a bit more, increasing the overall belt tension. Of course the degree of shortening vs the resulting tension increase is kind of trial and error, unless we measure the result. We would not want to "over-tension" and cause trouble with the spindles and pulleys, right?
Another possibility is to replace the tensioner spring with something heavier (if one is available) or ( shudder) maybe an adjustable one?

I have just opened a case with Gravely, and in due course I will ask them about the belt tension. I am curious to find out about their "anti vibration kit", and any other suggestions they may have.

What say you all?


#165

C

coder

bullet bob said:
Coder. With all due respect sir, I think you need to have a nice long talk with your dealer. This should be your first step.....
Click to expand...
You are right.. I am just dragging my feet. I expect they will tell me "They all do that, it is normal",
and I am not looking forward to hearing that. How many of you heard that answer?
(I know it is stupid, but let's see how far I get with Ariens.
At the very least Ariens will answer my explicit questions, such as what is the belt tension supposed to be, or
whether they have a kit to deal with this. Supposed to be a well-known issue.).

I am reading that the allowed deflection is 1/64" for every inch of span, and this particulate belt
segment has a long span. This is at 10 or 12 LBS pressure to create a deflection.

I have also asked them about the max air restriction of the Kawi Fr691 engine
(I am in the process of putting a filter minder on it).

Ariens got back to me and recommended putting on a "shorter belt", remarking that the vibration does not
effect cut quality. Cut quality is fine, my concern is that the excessive vibration will lead to
premature wear of various deck parts. No mention of any "anti-vibration kit".

They did not say anything about how much shorter, or what the belt tension should be.
Sounds like they are encouraging me to run with scissors. Mediocre!

I made a mistake of assuming that spending 7k ( with the bagger)
would buy me something that works well without any issue. Live and learn, I guess.


#166

C

coder

coder said:
Ariens got back to me and recommended putting on a "shorter belt", remarking that the vibration does not
effect cut quality. Cut quality is fine, my concern is that the excessive vibration will lead to
premature wear of various deck parts. No mention of any "anti-vibration kit".
Click to expand...
They told me the vibration issue is known to them. They recommended to put on a PTO belt 1" to 1.5" shorter than what it came with.
Sorry, said they, they do not have such belt. And of course I have to pay for it...

Pretty lame. I am using it as it is for now, hoping that it will "wear in".
The length of the belt is unclear. Parts diagram says 98.5", Ariens say 102" . I have to take it off and measure it.
The plan is to measure, find an aftermarket belt 1": shorter, balance my blades and see what happens.


#167

C

coder

BTW just put a Donaldson housing on my FR691. Since it has a threaded hole for a filter minder already, I put a JD filter minder on it which measures the highest restriction
that occurs during operation in the range of 0-8" water column.

Did mow with it, and it measured < 1" restriction. So as far as I can tell, putting a cylindrical filter (and the safety inner filter) on this engine does not cause high air restriction,
like some folks asserted it would. Based in this, it seems to me that the myth that a cylindrical filter/ housing combo would cause the engine to run rich (or having any other
negative consequence) is busted.

I believe the only way an air filter can cause an engine to run rich is by causing an air intake restriction. I do not see any other mechanism.
If the filter is unable to deliver the air volume the engine needs, that will also manifest as increased air restriction.

Needless to say a high end cylindrical filter set and housing is superior to the tiny OEM filter in every other way.
E.g..: Air filtration quality, longevity, and operational robustness (by virtue of having a secondary, safety filter)

I am willing to reconsider my point based on a rational argument, am I missing anything?


#168

C

coder

Just to be clear, the air volume delivery capability can be stated as: The air box and filter(s) are able to pass through X CFM air, while causing no more than Y
inch ( water column) air flow restriction at the engine air inlet. The "air restriction" caused by a new air filter is not a fixed value.
It is an air restriction curve, plotted against the air volume. This plot shows a non-linear function. (Source: Donaldson filter collateral)

But in this case, we are not trying to estimate the restriction, we are measuring it directly under actual operating conditions.
And we have seen the measurement, and it is good.

PS. If you are interested in the max air volume pulled by the Kawi FR691, I calculated it using Donaldson's formula with these inputs:
CID = 44.3 RPM: 3600 VE: 90% Air volume at max RPM is: 41.5 cfm.

The Volumetric Efficiency maybe less, but that would just drop the air volume needed further. At 80% VE it would only pull 36.9 cfm)
The Donaldson/Kawi cylindrical filter + safety combo is rated at 86 cfm @ < 8" (water column) nominally,
but we can see that the actual measurement shows a max restriction way lower than 8".


#169

B

bullet bob

What'd he say???? o_O;)


#170

cpurvis

cpurvis

bullet bob said:
What'd he say???? o_O;)
Click to expand...
(in a raised voice) HE SAID THAT THE DONALDSON DUAL-ELEMENT AIR FILTER SYSTEM IS THE CAT'S MEOW.


#171

C

coder

Sure.

Making a case for this upgrade. It is a worthy upgrade on multiple levels.
The solution (complete with the filter minder) takes the guesswork out of air filter changes,
and contributes to the longevity of the engine. (Mainly by cutting down on airborn particles entering the intake, by virtue of
its superior filtering efficiency) It also decreases the number of air filter changes needed.

Next, somebody is going to ask, if it is such a great option, why Kawi does not just slap this air box on their FR or FS engines to begin with?
Or why do they not provide this as an upgrade? I good question, IMO. They should. Maybe they will, at one point.

I guess they want to give us some incentive to spend the $$$ on Pro model ZT-s with one of their "pro" engines.
The "differentiating" between the 3 levels of air filters available is entirely marketing driven.

For example, the entry level filter is just the flimsy, tear-prone paper filter. If you look at the engine service manual,
one of the recommended steps for filter inspection is to check for tears in the paper media. Great..

The next option is the same thing, but with a foam prefilter added. (How did they make a case for not having a $1 foam pre-filter?)
And the best option is a cylindrical filter, except they do not seem to want to provide that for "entry level" engines.


#172

cpurvis

cpurvis

Adding a good air filter to the entire engine lineup would add cost. Unless ALL manufacturers did it, know-nothing-except-price customers would flock to the ones who can sell for less by putting a cheap filter system on their engines.

P.S. We're in the wrong thread. This one is about the Gravely 52" deck vibration issue.


#173

C

coder

Yes. sorry about that, got carried away... I promise not to post about ai filters here.


#174

B

bertsmobile1

It is all about the ticket price
There is 5/8 SFA difference between the FR & FS engines and it probably cost Kawasaki more to make the 2 variations than the difference in the wholesale price.
However Joe Public wants CHEAPER even if they are buying the top shelf engine on offer for a particular mower they still want it to be CHEAPER .
Thus the FR, FS & FX variation of exactly the same engine .
OTOH commercial customers can claim the mowers purchase price as a tax deduction of some sort so purchase price is not a problem for them in their heads .
Longevity & reduced maintanance time / cost is tops in their minds and the canister , fit & forget till it tells you to replace it is just the thing they want .


#175

C

coder

OK.. back to the original topic: deck vibration.

On my 2021 model Ariens Apex 52, the PTO belt tensioner pulley arm has 2 mounting position for tensioning pulley, (and the belt safety "finger")
I can move these to the mounting holes to the left of the current factory position, and this will effectively increase the tension of the PTO belt slightly.
I think I like this solution more than I like the solution Ariens support recommended: "Buy a shorter aftermarket belt".
When I do this I will post pictures.

Just got my handy belt tension measuring tool, will measure the tension "before" and "after".

Now I just need to figure out how I can get at the blades, so I can take them down and balance them.

I have a couple of rapid racing jacks, I was thinking of just jacking up the front, putting one of the jacks in the middle , under the balancing weights.
Should be strong enough there.

PS. Changed my motor oil @6 hours to Redline 15W-50, and the original Kawi filter to Fram UG4967. Seems to run noticeably quieter.
My idle used to have a bit of "syncopation" to it, it is now evened out.


#176

C

coder

Following up on the deck vibration topic.

I measured the current PTO belt tension. The common sense guideline suggests 1/64 inch deflection for every inch of segment length using a deflecting force of 10 lbs.
The segment in question is 72 inches. According to the generic principle, deflection should be 1 and 1/8" . I measure 1 5/8". So this belt does not appear to have enough tension.
And, as I observed before, it did did not look to me it had enough tension to begin with, with the way it is dancing around like crazy.

The tensioning arm has 2 possible positions where the pulley can be mounted. It came from the factory with the pulley mounted in the lower tension position.
Or perhaps it was part of the dealer's de-crating and assembly. I am optimistic that remounting the pulley will take care of the vibration, easy enough to change.

What disappoints is that Gravely /Ariens tech support did not know what the tension should be on this belt, nor it is in the service manual
and the support people were unaware that the tensioning pulley had 2 possible mounting position.

I am trying to figure out how to get at the blades without dismounting the deck, so I can take them off and balance them. I have a pair of ramps for working under my cars, maybe
that is good enough, given an impact gun. I see some Zt mower lifts on Amazon and HF, with a crossbar and "baskets" on each end of the crossbar
for the front wheels, it that what everybody uses?


#177

C

coder

I did the "reposition tensioning pulley to increase belt tension".

Repositioning the tensioning pulley made the deck vibrate less overall, esp at full RPM. Instead of the belt section whipping between the pto and the center pulley, now the tensioning arm is bouncing excessively. Ariens tech support suggested to put on a belt an inch shorter, "unfortunately they do not have one in stock" .
They seem to have a 127", 5/8 belt : 7239300 Ariens Gravely PTO Mower Belt 5/8" x 127" B124 5L127

They said "you may want to find an aftermarket belt" .

I asked them to ship one to me, and state in a letter that I am allowed to put on the 127 belt s per their recommendation.
as a fix for a warranty issue. I want to avoid voiding my warranty because of performing an "unauthorized modification".
Talked to my dealer. Not surprisingly, not very useful. They want $40 to pick up the mower so the can look at it.


#178

M

MParr

@coder
I use a floor jack to access the blades. Use jack stands for safety.
I have a DeWalt cordless impact to remove and install the blade bolts.


#179

N

NealS

We purchased a ZT HD 52 in 2017. We have about 200 hours on it. We have been following the noisy deck problem for some time. We did add a idler pulley for the long side of the belt that seemed to be slapping so bad. Also pressed an indention into the pulley cover, to create clearance, which was rubbing on a bolt, or maybe stud. We have thought that most of the harmonics had been cured. The other day we experienced something that made this flash back into my mind. Have no idea if it could be part of the problem.
We had made a lift, to pick up the mower with the front end loader on our tractor, so we could stand upright to work on the underside of the deck. We were using a pressure washer to clean the deck underside. While doing so, we noticed, when we hit the underside of the deck, just right, it would give off a rattle sound. I think it must be where curved metal behind the blades (grass deflectors, one each blade) lays against the rear side of the deck housing, causing a viberation between the two pieces.
We wonder if it might be possible for this to be an overlooked viberation noise, some of us are hearing?


#180

C

coder

It looks like this mower deck used to have a severe harmonic vibration and I think they fixed this to some degree by incorporating the "anti vibration kit" they were giving people to try out. I am thinking this, because the original tensioning arm used to be black, and now it is silver, just like in the kit. I think, the problem I am describing is not quite as bad. It is just excessive belt slapping now.
The current manufacture Ariens/gravely does not have any more problem with harmonic noise or the belt rubbing on the guard finger.
I got my 1" shorter V belt (Scag 127" x 5/8" ). Put it on today, did not seem to make much difference. I have to try putting the tensioner pulley back in its original position on the tensioner arm.


#181

C

coder

NealS, what did you do, drill out the deck for the extra pulley? Did it help? How did you prevent the deck from rusting there, where the powder coating is
drilled out? Sounds like a rational mod, I am just worried that they would cancel my warranty on the deck.
Unclear what you mean by "pressed and indention.." . I think you mean the one of the belt keeper fingers, that maybe is too short in this case?


#182

U

UFLBret

Hello all, I read the first 10 pages but didn't have time to read the rest. I have a ZTX-52 mower I bought new 2 years ago for our small 5 acre farm. I used our tractor with 6' bush-hog for the heavy lifting. Mainly use the mower for fence lines and common areas around the house, etc.
When i first got the Gravely i noticed the vibration, it irritated the heck out of me. It was only when the pto was in operation and the hard part to figure out was it was intermittent. Went online and saw it was a rather common issue. At about 25 hours I figured I should sharpen the blades but we were in the process of moving out of our trailer and into the house we built on property so I didn't have a lot of free time. I just went and purchased a new blade set on Amazon. After I changed the blades I haven't experienced the vibration. I'm really perplexed that nobody mentioned it could be a blade issue. It fixed mine, may be worth looking into for others as well. Has anyone with the vibration changed their blades?


#183

M

MParr

@UFLBret
I think blade imbalance has been mentioned. Another thing, some Gravely blades are offset. If you were to lay a Gravely blade down on a flat surface, the mounting hole will be about 5/16” above the surface. These blades are stamped and the angles can be off. This can be verified with the blades on the machine. Measure from the ground to the bottom of the blade and record the measurement. Rotate the blade 180 degrees and measure again. If the numbers are off, the blade is not uniform and will cause cavitation. Cavitation causes vibration.


#184

U

UFLBret

MParr said:
@UFLBret
I think blade imbalance has been mentioned. Another thing, some Gravely blades are offset. If you were to lay a Gravely blade down on a flat surface, the mounting hole will be about 5/16” above the surface. These blades are stamped and the angles can be off. This can be verified with the blades on the machine. Measure from the ground to the bottom of the blade and record the measurement. Rotate the blade 180 degrees and measure again. If the numbers are off, the blade is not uniform and will cause cavitation. Cavitation causes vibration.
Click to expand...
I can say that since I have replaced the blades the mower has cut better than it did when it was new, I can mow faster without windrows and it discharges better from the chute as well. Currently have about 50 hours on the machine now.


#185

C

coder

UFLBret said:
Hello all, I read the first 10 pages but didn't have time to read the rest. I have a ZTX-52 mower I bought new 2 years ago for our small 5 acre farm. I used our tractor with 6' bush-hog for the heavy lifting. Mainly use the mower for fence lines and common areas around the house, etc.
When i first got the Gravely i noticed the vibration, it irritated the heck out of me. It was only when the pto was in operation and the hard part to figure out was it was intermittent. Went online and saw it was a rather common issue. At about 25 hours I figured I should sharpen the blades but we were in the process of moving out of our trailer and into the house we built on property so I didn't have a lot of free time. I just went and purchased a new blade set on Amazon. After I changed the blades I haven't experienced the vibration. I'm really perplexed that nobody mentioned it could be a blade issue. It fixed mine, may be worth looking into for others as well. Has anyone with the vibration changed their blades?
Click to expand...
I just did. Have 10 hours on my 52" ari apex ( about the same as the gravely hd). The factory new blades were rather badly out of balance. I have a wall mounted ball bearing blade balancer. Took me 1/2 hours per blade to get them balanced.
Runs noticeably better in every way with the new blades, although I still have belt slapping.


#186

G

Goldwing

Cphillips82 said:
The plot thickens...I just spoke with a different dealer than the one I bought mine from. Because this dealer sells so many Gravely's they speak frequently with higher ups at Gravely and there IS FOR SURE AN ISSUE WITH THE 52" ZT HD. The 60" and 48" don't make the rattle but it is a common complaint that Gravely is aware of (though they probably won't admit it now until there's a fix). The person I spoke with was very helpful and took a lot of time to talk with me despite it being of no benefit to them. She will give me a call as she finds out more and if there becomes a recall.
Click to expand...
I have the ZT HD 48 and it "Rattles" a lot. They do sell a fix kit, but not all dealers have it yet.


#187

G

Goldwing

I've got over 150hrs on my ZT HD 48 mower. Its rattled from day 1. I have to keep an eye out for loose bolts every where. I've replaced the dust cover on the left front wheel bracket 3 times, even tried to silicone it on. Not the kind of craftsmanship I expected from Gravely. It mows great, just have to keep replacing missing parts!


#188

A

ariensapex52gg

Hello all, I got locked out of my old account somehow. I think I have finally solved the issue with the deck rattle/vibration and it was accidental. Since buying the machine I have never been unimpressed with the power it has but have always felt that the engine speed even at full throttle was slower than it should have been so I borrowed a digital tachometer from another machine that measures the rpm's by wrapping a cable around a spark plug lead and found the speed to be 2800-2900rpm at full throttle. The machine I have has a Kawasaki fs691v engine which should run at 3500+/-100rpm according to info I found online. so I adjusted the throttle linkages and sped the rpm up to 3500. the difference was remarkable and I instantly noticed NO RATTLE at full throttle. If I slowed the engine down to the speed it previously ran at the rattle came but it goes away when sped up almost like a "critical point" on some cars where they will vibrate only at a certain speed. Obviously it also cuts much better now, throws grass farther and is physically faster as well. I highly recommend buying a digital tachometer from amazon and testing it for yourself. Its an easy thing to do and has absolutely transformed the machine.


#189

7394

7394

Goldwing said:
I've got over 150hrs on my ZT HD 48 mower. Its rattled from day 1. I have to keep an eye out for loose bolts every where. I've replaced the dust cover on the left front wheel bracket 3 times, even tried to silicone it on. Not the kind of craftsmanship I expected from Gravely. It mows great, just have to keep replacing missing parts!
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Loctite 1648259189087.png


#190

M

MParr

Goldwing said:
I've got over 150hrs on my ZT HD 48 mower. Its rattled from day 1. I have to keep an eye out for loose bolts every where. I've replaced the dust cover on the left front wheel bracket 3 times, even tried to silicone it on. Not the kind of craftsmanship I expected from Gravely. It mows great, just have to keep replacing missing parts!
Click to expand...
I’m on my second Gravely in two years. My former Pro Turn 160 was excellent in every category except the Yamaha engine. My new Pro Turn 260 is solid, even the Kohler engine. Would I recommend a Gravely? Heck yes, as long as it doesn’t come with a Yamaha engine.


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