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View Full Version : Gravely 34Z...10 inch tires won't fit?


hackitdown
06-14-2011, 10:00 AM
I have a Gravely 34Z with stock tires (7.5"?) and rims, and really terrible traction on hills. I researched here on lawnsite regarding the traction problems, and several guys suggested Turfmaster 20-10-10 tires. The guys said they mounted them on the stock rims, and that helped the traction issue. So I ordered a set.

When I brought the tires to my mechanic to be mounted, he says they won't fit on the rims. I have to say, they do look way too wide for the rims. Is he wrong? Does my machine have smaller rims than most? And it is hard to visualize those huge tires fitting in the wheel well area of the Gravely.

Will they fit? Do I need new rims?

Any help would be greatly appreciated. Thanks very much.

topsites
06-14-2011, 10:20 AM
Well gosh if your machine currently has 7.5" tires doesn't it stand to reason that the rims are made for that size tire?

I mean I am sorry but you know, you can fit some off-size tires on a rim but to a point, for example...
Assuming your rim is made for 7.5"s, you can probably fit anything from a 7" to an 8" on there
and you might be able to spread out as far as 6.5" to 8.5"...
Maybe, safely you can fit 7" to 8" and no more, that's assuming the rim is made for 7.5"s but certainly no more than an inch either way.

Then...
Lets just say we're already at the far end of the spread now, which is highly unusual because machine manufacturers
tend to stay within certain parameters rather than to the edge, but lets just assume that the 7.5" on there was on the
very low end rather than middle of the road (meaning the rim was actually made for an 8.5")...
It's a stretch...
But in that case one MIGHT get up to 9.5" on there but nothing smaller than a 7.5" and yet it still
would be one heck of a gamble to think that anything much past 8" would fit.

The next problem we run into, with folks fitting off-size tires on a rim, is later down the road the half
won't know (or just as well can't remember) what size tire the rim was made for.

But your mechanic is right, a 10" no way.
You'd need new rims.

hackitdown
06-14-2011, 10:25 AM
Well gosh if your machine currently has 7.5" tires doesn't it stand to reason that the rims are made for that size tire?


Well gosh, yes.

As I said in the original post, several Lawnsite members said that they mounted 20-10-10 tires on the stock rims. Guessing and estimating is fine, and thanks very much, but can someone with actual experience with this clarify?

topsites
06-14-2011, 10:53 AM
I was hoping my not needing a mechanic to mount my tires would be experience enough,
but can you tell us where you saw LS members talk about fitting those 10" tires on your mower?

hackitdown
06-14-2011, 11:19 AM
I was hoping my not needing a mechanic to mount my tires would be experience enough,
but can you tell us where you saw LS members talk about fitting those 10" tires on your mower?

Thanks for your help? These are the posts from guys with the same mower, that bought the same tires.

http://www.lawnsite.com/showthread.php?t=345113&highlight=gravely+tires

http://www.lawnsite.com/showthread.php?t=338927&highlight=gravely+tires&page=2

http://www.lawnsite.com/showthread.php?t=339582&highlight=gravely+tires&page=3

nolanjim
06-14-2011, 11:29 AM
What is the tire size on your old tires. I had a 34z, great machine. The rims were 10inches, I think we upgraded though.
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hackitdown
06-14-2011, 12:07 PM
What is the tire size on your old tires. I had a 34z, great machine. The rims were 10inches, I think we upgraded though.
Posted via Mobile Device

The old tires are 21-7.00-10. The stock wheels are 10x6.

nolanjim
06-14-2011, 12:52 PM
Measure distance from tire to wheel well, if more than 1.5", it should fit. Others tried it and it worked just ask your mechanic to mount them.
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norwoodj
06-14-2011, 02:46 PM
we have one and i believe they were a 10 wide tire i put on it. flip the rims so there is more offset to the outside. that is what i did on mine and put valve stem on the otherside then you can still fill them easy.

hackitdown
06-14-2011, 04:11 PM
Update: I wrestled the 10" tires onto the 6" rims with my old motorcycle tire irons and soap, it took a while. The mechanic was wrong, they fit on, and I was able to fill them. The new tires rubbed against the frame a little, so I went to the autoparts store and bought spacers. The wheels/tires are back on the mower, but now because I used the spacers, the studs are a little short, you can see a couple of threads on the inside of the lugnut. Maybe longer studs will be the last piece of the puzzle. But how do you remove the old studs? The back side has no "nut" on which to put a wrench, it is rounded.

TNGrassCutter
06-14-2011, 04:38 PM
Knock them out with a hammer probably.
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fatboynormmie
06-14-2011, 04:56 PM
A little grinding on the gas tank bracket is all that is needed to make the tires fit.It dosen't take much grinding just enough to clear the bulge of the tire.Spacers will work but adds to the width of the foot print of the machine.Some guys are scared to do any mods to there mowers like grinding on it but I figure it belongs to me now and if I break it I'll fix it myself. This mower with larger tires is a little better on hills but don't expect miracles.I find the best advantage is a reduction in rutting and some added suspension comfort.

hackitdown
06-14-2011, 06:40 PM
A little grinding on the gas tank bracket is all that is needed to make the tires fit.It dosen't take much grinding just enough to clear the bulge of the tire.Spacers will work but adds to the width of the foot print of the machine.Some guys are scared to do any mods to there mowers like grinding on it but I figure it belongs to me now and if I break it I'll fix it myself. This mower with larger tires is a little better on hills but don't expect miracles.I find the best advantage is a reduction in rutting and some added suspension comfort.

Cool, thanks. I may try grinding the brackets if it is too wide for the gates. It now measures a little over 36". I just tested it on my own hill, traction is definitely improved a lot. I tried 15lbs in the tires. With the old tires, I found that rutting wasn't an issue. But they would spin so easily, even on level ground, that they would grind the grass right down to dirt. Maybe that is what everyone is calling rutting.

hackitdown
06-14-2011, 06:48 PM
Knock them out with a hammer probably.
Posted via Mobile Device

Thanks...now I get it. I thought they were threaded all the way to the head. I saw some youtube vids of how they have spline-like ends which seat in the hub.

fatboynormmie
06-14-2011, 10:28 PM
Cool, thanks. I may try grinding the brackets if it is too wide for the gates. It now measures a little over 36". I just tested it on my own hill, traction is definitely improved a lot. I tried 15lbs in the tires. With the old tires, I found that rutting wasn't an issue. But they would spin so easily, even on level ground, that they would grind the grass right down to dirt. Maybe that is what everyone is calling rutting.

In dry weather my unit didn't rut but when the soil conditions were moist the tires rolling over the lawn would show visible signs of compaction(rutting) .Also while using unit on tight lawns I slow the rpm's down on engine which in turn makes the hydro's a little less responsive and helps with turf tear while turning machine.