ZT52HD DECK VIBRATION FIX

[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.

 

[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).

 

[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

 

[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......

 

[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.

 

[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...

 

[my87csx481]

@countryboy89: the dealer told me mine was normal too. 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.

 

[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.

 

[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.

 

[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.