Airing down tires

[Dougw133]

Hi, Have a Mahindra 5035 HST. Got it about 2 months ago. Now that the weather in the northeast finally seems something like spring I am getting out and getting projects done. I have the R4 industrial tires. It some areas I leave some chunks and ruts where it seems it's not a swamp but maybe slightly more saturated. I am to use this for pulling a 7 Foot Rear Finish Mower. Today I used the FEL to rip up sod for an area of garden. The 4 or 5 trips in the same spot into where I was working left 6 inch deep ruts. Not muddy, but ruts.

I got a suggestion to let some air out of the tires. Anyone have any advice as to how much? How much will this actually help?

Thank you

 

[Deere Dude]

Maybe de-airing tires would work, but I don't think I would do it. I would hate to take a little to much out and run one off the rim because I worked it a little to hard.

 

[bcp]

One measurement I remember from long ago for soft sand was to let air out until sidewall height was not less then 2/3 of normal height. That probably won't be as universal now with some tires being of a wider cross section.

Bruce

 

[RaydaKub]

Of course making the surface area of the tire larger (via deflation) would give you some additional floatation. But I doubt it would be enough to make much of a difference, especially doing loader work. The front tires already have a smaller footprint, but then you add the weight from the FEL and you'd have to be careful to not break the bead.

 

[Soundguy]

i agree.. I'd be a lil leary of underinflating a tubless... fine line between usefull extra traction, and running it off the rim in a turn with a lil side force from rutted mud or debris on a sidewall..

 

[Dougw133]

Thanks for the replies. Perhaps removing the Fel for mowing would help..?

 

[Don87]

That's a 2 and 1/2 ton tractor, any weight you can remove for yard work will probably help.

 

[pat32rf]

A lot depends on just how much air is in the rear tires now. Mine was delivered with far too much air. The tires said NOT to inflate over so many pounds while mounting. THAT is the pressure they were delivered with.
In my younger days I used to run large radial tubeless tires on my 4x4. They were rated to carry 2500lbs each, at 45psi. I ran them hard on a 4000lb truck, at 10psi with no problem. At 8psi they started to "look soft" when on a hard surface, but at 10-12psi they ran fine on pavement or mud, as long as I kept speeds below 65mph. (sacrificed a few mpg)

 

[Groo]

First check to make sure they are not over inflated. After that; airing down would help, but I would only do it with the FEL removed. Removing the FEL would defiantly be the thing to do for mowing.

 

[Gary Fowler]

Check your tire pressure, I suspect that they came with max air in them to make them ride better during transit and not bounce. My LS had over 20 PSI in the rear. I reduced it to 12 and I think it is still a bit high for max traction. Normal rear pressures is 8-12 depending on what load carrying you are doing and if you have maxed out rear wheel weights etc. Since most CUTs dont come with wheel weights, you would likely be good with 8-10 PSI. With FEL you need to keep them aired up more so than the rears due to the turning forces with a full load if not properly inflated, you could roll one off the rim.
On the rear, you should see a bit of a bulge in the sidewalls and full tread marks on dry pavement.

 

[RoyJackson]

I assume those rear tires aren't filled with liquid?

The intent of lowering pressure is to get more tire patch on the ground. More tire patch means less weight per square inch of patch...also means more surface area (of the tire patch) for traction.
It can't hurt to try this and see how it works...like other's wrote, remove the loader first and make sure you increase pressure before you re-install the loader.
Also...don't go overboard on reducing the pressure. You could break the bead if the tires slip on the rims.
My suggestion is to wait until that ground dries up before you mow.

BTW, lowering tire pressure also works well to increase traction in snowy conditions...and not just for tractors. If you do this with a road vehicle, just be advised lower pressures increase heat...not a problem with a low speed tractor, but can definitely be a problem with a road vehicle.

 

[Mark Page]

I used to fish the surf on Maryland's coastal beaches. 15 psi used to work well. Always reinflated when I got back on the road. Some guys went down to 10 psi but that always seemed a little risky.

 

[MHarryE]

Not sure what size tires your tractor has. My Kubota L5740 with loader and rear wheel weights weighs 6900 pounds. The rear tires are 17.5L-24s 6 ply rating. At 20 psi the load rating per tire is 4400 pounds. My fronts are 10-16.5 with load rating 3500 pounds at 45 psi. My manual says to run at the maximum inflation pressure so I have 15,800 pounds of load capacity. The Tire and Rim Association lists that as the minimum inflation pressure for the R-4 tire but for a 17.5L x 24 ag tire (I haven't seen that size in anything but R-4) the T&R Assn says it can go down to 12 psi and will then have a 2500 pound capacity per tire. It looks like you should not have a problem dropping to 12 psi as long as you don't exceed 5,000 pounds on the rear axle, but the book has a caveat for that. The load limit can be exceeded by 33% if you don't exceed 10 mph and 22% if you don't exceed 15 mph. My understanding is the tractor companies use the maximum because they have no control over the implement you hang on back or how much you put in the bucket of your loader - up to hydraulic capacity.

 

[Dougw133]

I checked my pressure and they are at 35psi. Max per the tire is 44psi. I removed the loader and mowed my field. Small ruts but no damage to soil or grass. No, they are not filled