Rear tire pressure

[pauleqer]

I've done some searching around and seems that around 15psi seems to be the number for a lot of peoples rear tires. When I got my DK40SE in the spring I had checked them as was suggested on here. They were at almost 30psi and rock hard(R4's). So I had lowered them both to 20psi and see how things go from there. Turns out that turning uphill towing anything(haybine, 3ph rake or baler), it stops dead in its tracks and inside rear just spins digging a hole and must use 4wd. Problem is in 4wd the fronts tear the heck out of the field whenever I make a sharp turn, as I had figured it would.
They are filled with rim guard and I now have them all the way down to 10psi with not much change at all. Still rock hard and sidewalls don't squat one bit with about an inch of tread inside and out not even touching the ground, and that's on grass as I have no concrete park it on yet. Winter is coming and I cant imagine using rock hard tires in the snow, especially plowing backwards as I cant even back uphill with nothing but the loader(empty) without 4wd engaged(id say 15-20 degree slope maybe? not what I would call steep).
How low can I possibly go before causing the tire to pop off the rim? Maybe im using the wrong gage? Im using a regular silver automotive one that I clean real good afterwards. If I go lower ill need a smaller scale gage, where can I get one of them? Any other suggestions?
Sorry for the long post, tried to get as much info in as I could.

 

[George2615]

Backing uphill (with or without snow) in 2WD is tough for any tractor with a loader to do due to weight transfer. Even with chains on its tough. I have my rears filled, use chains, and 4WD to plow snow. My tire pressure was set 18-20# when it was 70 Deg. In colder temps they read about 15-17#. That's as low as I'll go. My gauge reads in 2# increments. I wouldn't go any lower in air pressure than what you are. R4's are hard industrial tires. Not like soft lawn (turf) tires. You could let all the air out and the tire won't have much give or flex.

 

[TJP89]

George said it, and I agree. Also, R-4s aren't the best traction wise, and they aren't made for field work either, that's the R-1 Ags. On my CK35, I have ags, and the pressure is about 20 psi, if I remember correctly. Also, my CK tears up the yard in 2WD M unless it's really dry, so your heavier DK would certainly tear things up. I consider that something that comes with a real tractor, it's going to tear things up unless you're really careful. So I'd say, use 4WD when necessary, because I don't think the tire pressure is your problem.

 

[oosik]

I have R-1's at 20 psi in the rear. I had a thought - what is the ply rating on your R-4's. That could have a lot to do with them remaining rock hard. My rears are filled with Rimguard also. I wouldn't go below 20 psi in the rears. At 20 psi my rear tires JUST make full width contact with dry ground.

 

[ritcheyvs]

What does your owner's manual say? I suspect it's about 35psi for R4 rears. You really don't want to roll a tire off the rim, especially a loaded rear.

 

[Scrambler82]

I run loaded rear tires, never checked the pressure.
Only time I would even look is if I saw a trail of beet juice on the ground.

Question.. Is there a preassure that loaded tires should be at ?

 

[thatguy]

I run loaded rear tires, never check the pressure.
Only time I would even look is if i trail of beet juice on the ground.

Question.. Is there a preassure that loaded tires should be at ?

On my 2320 (loaded R4 rears) I was running about 12 to 15 - AFTER reading on here I pumped it up to about 20..

20 psi was too much, even at slow mowing speeds it would bounce you off the seat at the slights bump..

I have since dropped it back to around 12ish..

Brian

 

[thatguy]

I run loaded rear tires, never check the pressure.
Only time I would even look is if i trail of beet juice on the ground.

Question.. Is there a preassure that loaded tires should be at ?

On my 2320 (loaded R4 rears) I was running about 12 to 15 - AFTER reading on here I pumped it up to about 20..

20 psi was too much, even at slow mowing speeds it would bounce you off the seat at the slights bump..

I have since dropped it back to around 12ish..

Brian

 

[davrow]

Question.. Is there a pressure that loaded tires should be at?

Loaded or not should not make a difference. Only the air is being compressed.

The goal is maximum contact patch, but that is not always possible with stiff sidewalls as R4s have. Then it is 'as low as possible without endangering the tires integrity'.

 

[George2615]

I run loaded rear tires, never checked the pressure.
Only time I would even look is if I saw a trail of beet juice on the ground.

Question.. Is there a preassure that loaded tires should be at ?

As mentioned it doesn't matter whether they are loaded or not. Tire pressure should be set at the manufacturers recommended pressure found in your owners manual. Sometimes you may need to lower the pressure to get full tread contact on the ground. This can be checked by driving through soft material such as sand, snow, mud etc.

 

[pauleqer]

I believe they are 8ply. Not totally positive but I think the owners manual says something like 25 or 30psi. If it is because they are just "stiff R4 tires" then my thing is, why would they(Titan I think) even make a tractor tire that? Can only use about 75% of the tread, if that. Id say on pavement that its less than that as the ground compresses a bit. Even with my 5ft brush mower hanging off the back and no loader on, the things are hard as a rock and perform the same way.

 

[Scrambler82]

Thks for the input, I will check out the OEM pressure specs.

 

[ritcheyvs]

With loaded tires the air volume is small compared to unloaded. This will make the tires feel hard because even small compression makes the internal pressure (in that small air volume) spike much higher than unloaded (because the liquid is incompressible). But also, even a small loss of that air will decrease the internal pressure a lot (because there is so little air in there). Considering how inconvenient it would be to roll one of those beads off the rim, I do check my loaded tire pressure, at least in the spring (after the tractor has sat unused) and fall (when temperatures (and pressures) drop).

 

[Scrambler82]

With loaded tires the air volume is small compared to unloaded. This will make the tires feel hard because even small compression makes the internal pressure (in that small air volume) spike much higher than unloaded (because the liquid is incompressible). But also, even a small loss of that air will decrease the internal pressure a lot (because there is so little air in there). Considering how inconvenient it would be to roll one of those beads off the rim, I do check my loaded tire pressure, at least in the spring (after the tractor has sat unused) and fall (when temperatures (and pressures) drop).

Wonder if you followed the Manufacturer's specs on air pressure ?
So far we have anywhere from 12 to 20 psi.
I will have to check my book on the new tractor once it gets here to be sure of what the Mahindra calls out.
Waiting for the thumb, tire filling and shipment.