Grass isn't cut between the blades.

[jviews12]

Thank you for the picture. Was helpful in understanding problem. Maybe front blade dull?

 

[Joed756]

I'll measure them tomorrow. I have a 60" mower, so I assume the blades should be around 20" each. I remember reading that the Cub Cadet Tank mower has overlapping blades and the pulleys and belts have teeth so that the blades are positioned at 90 degrees to each other when the belt is installed so the blades won't hit each other when turning. The teeth in the belt and pulleys prevent the belt from slipping as you don't want the blades to hit each other. The overlapping blades keep the striping from happening. Yep, I just found it online. The 60" mowing deck uses three 21" blades. That's 63" of blades for a 60" deck. Maybe Gravely should consider this design.

In case you're unaware, the blades are measured diagonally. That's why you can have 63" on 60 " deck. Also, sloing down your mower speed can sometimes get rid of those stripes. The first thing I would check is belt tensioner(2)

 

[eyekue138]

Get an Exmark or a Bad Boy.

 

[MParr]

Get an Exmark or a Bad Boy.

You’ve got to be kidding.

 

[TobyU]

Someone who was talking about the computer software and models etc, which is way overkill for this and I doubt it helped them solve their problem at all, was talking about the faster you spin the blade the better.
This is not actually true.

In the arena we're dealing with it probably is because we're probably not able to get a blade to spend consistently at too high of a speed in any type of grass but you can certainly lower your quality of cut by spinning a blade too fast!

There are a lot of other factors at play here and you're not going to determine them all with a computer model or program because you would need some very sophisticated scientific measuring devices and you would have to test repeatedly and test a multitude of decks to actually come up with a theory or consensus.

Back to the problem though, it seems that the first thing that comes to mind is that Center blade is certainly not spinning fast enough for much at all. I don't recall the original poster ever answering the question of making sure if that blade was on the correct direction..
I get a handful of hours every season in with the blades on upside down and the customers have no clue that they are not cutting properly!

If the blade is then I suspect the belt is slipping on the pulley. You should be able to check this fairly easily by engaging the blades and just sitting there not even mowing anything for a few seconds to maybe a minute and then turn it off and start to feel the other pulleys and see if the center pulley is noticeably warmer than the other ones.

You might have to run a couple of minutes for this but I have found this problem before.

I've also had several gravely and ariens machines where the belt tension was way off for several different reasons but the main answer was to put a new belt on it and a new spring or a shorter spring or relocate the spring mounting point on the deck.

All I know is if that Center blade was spinning faster and maintaining its torque and speed, it would be cutting better than that.

 

[Freddie21]

When cutting taller grass, weeds, raise the deck and cut then lower and recut. The front of the deck will flatten the grass and it may not have a chance to be sucked back up to be cut.

 

[d19john]

When cutting taller grass, weeds, raise the deck and cut then lower and recut. The front of the deck will flatten the grass and it may not have a chance to be sucked back up to be cut.

When cutting taller grass, weeds, raise the deck and cut then lower and recut. The front of the deck will flatten the grass and it may not have a chance to be sucked back up to be cut.

Do as Freddie21 suggested, and I’ll add:
If all
Other suggestions have been checked, then try mowing in the late afternoon or evening when the grass is dry. Even on a day without rain, the grass can be very damp in the morning from dew overnight.

 

[bertsmobile1]

View attachment 68812View attachment 68812
Any closer and they will be slapping each other

Those blades are way too far apart
When using Gators I often have to buy a longer set & grind then down to fit
You measure blade spacing cutting tip to cutting tip
And cutting tip to cutting tip those blades will be 1/2" apart
The end of the blades often has to rake backwards from the tip to the flute
The blades are too short .

 

[Alan46]

Is there a way to fix the problem of grass left uncut between the blades? It is particularly bad between the left and center blade. I removed the relatively new blades (installed about 2 months ago), and rotated them, L to C, C to R, R to L, and I get the same result...2 stripes of grass the entire length of my mowing, which means I have to mow over the same path a second time, but slightly moved to the side to make sure my blades cut the 2 stripes that are left between the 3 blades. The grass between the left and center blade is up to 12" wide, while the grass left between the center and right blades is about 2-4" wide. I have the ProMaster 260.

Did you ever get the problem fixed?

 

[HoustonDave]

Coincidentally I always get a strip of poorly cut grass at about the right side of the left blade/center blade overlap. John Deere 62" deck. Blades factory new measure 20 9/16" long. I replaced my blades, then looked at the upper side of the deck and the idler pulley was tilted! The lower bushing was almost worn in half. $75 for new bushings and pulley and a new belt later, all seemed OK until I cut any grass and found the blades were turning slowly - found that in replacing the belt it slipped over the engine pulley. Got that sorted, and it cut very well - this is the second time I have had to replace that pulley though in maybe 450 hours. JD dealer said the three pulleys need to be replaced every year or so, but the other two are un replaced and work fine. The idler pulley is the only one with a grease zerk (which I use religiously) so you would think it would wear slowest, not fastest.
BUT...yard got cut - this time of year my grass grows an inch a day so going a full week between cuttings is not possible.