Tire pressure question

[Oldbinder]

On my rear tires (14.9- 24 R4) only has about 50% of the thread in contact with the ground. The instructions on the tires only say to not exceed 38 psi and the pressure is presently at 20 psi. The tires have rimgaurd in them and only 120 hrs on them. Even with a 6 ft Woods box scraper on the 3 point hitch the tire contact stays the same. Just having 50% of the tire in contact with the ground doesn’t seem right. Can I or do I need to decrease the pressure in order to get full contact?

 

[JethroB]

I’m running about 12 in the rears now mostly for ride comfort. It did increase the contact patch some but those R4’s have some pretty stiff sidewalls. Kubota manual recommends 20, Kubota dealer said go for it until you have slippage. Note running low pressure in the fronts you risk running the tire off the rim. BTDT. (No FEL)

 

[Chewwy]

You should follow the instructions in you operators manual regarding tire pressure. The manual for my Kubota specifies 20 psi for those size tires.

 

[deserteagle71]

I don't pay much attention to what an owner's manual says about tire air pressure. Whoever wrote the manual has no idea what you will be mounting on the tractor, nor how you will be using it. Pressure is set so there is a slight bulge in the sidewall of the tire - front or rear - for whatever work I'll be doing. The tread surface should have contact with the ground across its entire width, not just the center of the tire. If the tractor will be handling a lot of weight - like unloading 2000 lb pallets using the front forks- then I will air up the front tires accordingly. Then reducing the air pressure once the job is done.

 

[Oldbinder]

You should follow the instructions in you operators manual regarding tire pressure. The manual for my Kubota specifies 20 psi for those size tires.

My manual says the same thing.

 

[Oldbinder]

I don't pay much attention to what an owner's manual says about tire air pressure. Whoever wrote the manual has no idea what you will be mounting on the tractor, nor how you will be using it. Pressure is set so there is a slight bulge in the sidewall of the tire - front or rear - for whatever work I'll be doing. The tread surface should have contact with the ground across its entire width, not just the center of the tire. If the tractor will be handling a lot of weight - like unloading 2000 lb pallets using the front forks- then I will air up the front tires accordingly. Then reducing the air pressure once the job is done.

The front tires are ok, no need for me to adjust the pressure. I typically don’t have much weight on the 3 point hitch because most of the work is with the FEL. I need the full traction of the rears in the winter because I have to plow. I will try a lower pressure on the rear tires and see how things work out.

 

[LouNY]

I don't have R4's but my R1's are usually around 15 PSI .

 

[masseyrider]

I don't pay much attention to what an owner's manual says about tire air pressure. Whoever wrote the manual has no idea what you will be mounting on the tractor, nor how you will be using it. Pressure is set so there is a slight bulge in the sidewall of the tire - front or rear - for whatever work I'll be doing. The tread surface should have contact with the ground across its entire width, not just the center of the tire. If the tractor will be handling a lot of weight - like unloading 2000 lb pallets using the front forks- then I will air up the front tires accordingly. Then reducing the air pressure once the job is done.

I also do the eyeball test.
I'll add air when the sidewall starts to bulge depending on load.
I've never put a gage to the rears.
Close to 50 years and counting, no problems.
Drive your tractor over soft ground where it will leave a good clean impression.
I know my owner manuals show what it should look like.

 

[oosik]

I have R-1 tires on my M6040. 775 pounds of RimGuard in each rear tire. 1000+ pound blade on the 3-point. 820 pound grapple on the FEL.

I run 40 psi in the front tires. 16 pounds in the rear tires.

Drive across a sandy patch in my driveway. Jump off the tractor and check. It's OK - I have a full chevron mark - all the way across - for the rear tires.

 

[Too many Kubotas]

View attachment 962355On my rear tires (14.9- 24 R4) only has about 50% of the thread in contact with the ground. The instructions on the tires only say to not exceed 38 psi and the pressure is presently at 20 psi.

Wow. After 1,400 hours my M6040's rear tires look like new compared to yours.

Of course, 85% of the time there's something on the 3-point, but looking at the picture I can't help but wonder if you're spinning the rears somewhat frequently.

I don't use 4WD unless it's needed, which is when getting full scoops of dirt or rock with the loader, or when plowing if the snow is deep. I also don't drive it on pavement, which I'm sure helps.