Tires !! REAR TIRE PRESSURE ? !!

KoonHunter51 · Mar 18, 2015

FarmPro 2430 with 11.2 X 24 Farm Lug Rears
Just wondering what PSI you guys run in your tires
I have suspected that my rear tires are not aired up enough, 18/20 PSI & I do not think they are loaded with any fluid
I did a search on here & google & got plenty info that 15/20 PSI was required or that was normal so I ran with it

Well, did a little bushing today & one rear looked too low so I checked PSI & it was about 12 the other was 16
Got the manual out & did a kPa to Psi conversion
Front> 7.50x16> 210 kPa = 30 Psi
Rear> 11.2x24> 180/240 kPa = 26/34 Psi
I do have some steep places, so, Should I use the higher PSI or a little less ?
David

D0TC0M · Mar 19, 2015

As we do with jeeps we lower tire pressure to increase traction

George2615 · Mar 19, 2015

I have R4's and run the same 18-20 lbs. in the rears which is lower than the recommended. It gives the rears a little more flex when rolling and more tread on the ground for traction. I verified this driving through both mud and snow. At the higher pressure there was less tread in contact with the ground mainly at the outer edges of the tread. 12 PSI would be too low and may let the bead pop off the rim.

oosik · Mar 19, 2015

I have R-1's and run 20 in the rear and 30 in the front. The pressure is not dependent upon whether your tires are loaded or not. I have Rimguard in the rears.

This pressure gives my tires full bar width contact with the ground.

The Suburban Farmer · Mar 19, 2015

I have R4's and run them so that there is full contact across the bars when it's sitting on a hard surface like the driveway, but no bulge in the sidewall. That's the way my dad and uncles always taught me growing up, anyway. (My tires are filled with Rimguard.)

That comes out to being a little below the stated pressure, but it's worked well for me so far. I think you are better off being a little too light than a little to full.

ovrszd · Mar 19, 2015

Easy to tell if yours are loaded. Roll the stem down and push in the valve core. Liquid comes out, loaded.

Pretty hard to tell you how much air to run. We don't know your circumstances and the loads you are gonna put on your tires. On a tractor tire I prefer to be slightly overinflated, rather than underinflated.

buickanddeere · Mar 20, 2015

They are a balloon bias tractor tire, not a highway truck tire. What is the panic? A little squat or bulge is fine. On flat hard ground the tread bars should have near 100% contact with the ground.What is the weight on the rear axle? Check the tire manufacture's site, odds are 12psi is fine.

ovrszd · Mar 21, 2015

If they are tubeless there might be a panic running them too low and knocking them off the bead.

Running any tire too low on air pressure is extremely hard on the tire. This will show up in the tire's later life.

buickanddeere · Mar 21, 2015

Given the tractor's weight of 4380lbs, fuel operator and rotary cutter. 16-18psi is plenty. 12-16 without the rotary cutter. A dry tire is much easier and cheaper to repair after a puncture. Liquid CaCl ballast is only point is it's cheap upfront cost. pay me now or pay me later.

DK35vince · Mar 21, 2015

I run around 15 PSI in my loaded rear R-4's

KoonHunter51 · Mar 23, 2015

Thanks for all the replies;
Well, I feel like the 12psi in the rear was too low, I drove to the garage to add air &
if I had turned sharply on the asphalt, the tire looked like it would have come off the wheel.
The compressor gauge showed 10psi & my hand-held gauge showed 12psi
I added air up to 25psi on the rear & 30psi on the front.
Tractor goes fine up & down the steep hills mowing & doesn't feel lop-sided when turning.
David

buickanddeere · Mar 23, 2015

How much of the tread bars were touching the concrete when in the garage? It's a tractor tire designed for soft ground. Not a tire for a transport truck on the freeway. The tires are each rated for 1320lbs at 12psi and your tractor weighs 4380 with approx 2/3 on the rear wheels so 1460lbs per rear tire. If those tires were about to roll off the rim at 12psi. There is more going on here than we know about. at 25 psi each tire is good for 2000lbs and is maxed out if it's four ply rated.

Distributor: Farm Pro
Manufacturer: Jinma
Factory: China
Farm Pro 2430 Engine:
1.9L 3-cyl diesel
full engine details ...
Capacity:
Fuel: 7.9 gal [29.9 L]
Hydraulic system: 2.3 gal [8.7 L]
3-Point Hitch:
Rear Type: I
Power Take-off (PTO):
Rear PTO: live (two-stage clutch)
Rear RPM: 540/720
Dimensions & Tires:
Wheelbase: 72 inches [182 cm]
Weight: 4,380 lbs [1986 kg]
Front tire: 7.50-16
Rear tire: 11.2-24
full dimensions and tires ...
2430 Serial Numbers:
- Serial numbers unknown -
Farm Pro 2430 Power:
Engine: 30 hp [22.4 kW
Mechanical:
Chassis: 4x4 MFWD 4WD
Steering: power
Cab: ROPS canopy
Hydraulics:
Capacity: 2.3 gal [8.7 L]
Total flow: 3 gpm [11.4 lpm]

ovrszd · Mar 23, 2015

I think he should run whatever tire pressure feels right to him. He asked for opinions and added them to his judgment and made a decision. Sounds right to me.

buickanddeere · Mar 23, 2015

I'll take the results from the engineers in the lab and their testing over somebody's. "Well, I feel like ","if I had "," looked like it would have" and "doesn't feel lop-sided".
25psi will be running with the outside 1/3 of the tread bars off the ground. Do those Chinese tires have sidewalls like 2psi ATV balloon tires ?

ovrszd · Mar 23, 2015

buickanddeere said:
I'll take the results from the engineers in the lab and their testing over somebody's. "Well, I feel like ","if I had "," looked like it would have" and "doesn't feel lop-sided".
25psi will be running with the outside 1/3 of the tread bars off the ground. Do those Chinese tires have sidewalls like 2psi ATV balloon tires ?

And if that mentality makes you happy, it makes me happy.

I just don't think we have enough information to declare the OP incompetent in his decision.

I pay no attention to labeling to decide what pressure to run in my tractor tires. And I pay little attention to what they look like sitting on concrete. My tractor rarely works on concrete.

buickanddeere · Mar 23, 2015

The tread bar measuring on concrete is to obtain a repeatable base line to benchmark the tread pattern. With various weights, various pressures with various tire designs.

KoonHunter51 · Mar 24, 2015

b and d has way too much time on his hands
The tire probably wasn't going to come off the rim, but I wasn't going too make a tight radius to check either
I don't care what his reasoning is, I'm not gonna let no air from the tires, because the tractor goes where I, yes I, want it too
a whole lot better now

wonder why he didn't post mfr. suggested air pressure kPa, his engineers must know more than the mfr. engineers

I went to a local dealer with over 40 (Chinese & other) compact 4x4 tractors today and checked 9 rear tires
The lowest was 19psi the highest was 40psi,
The mechanic/salesman there recommended 5 to 10 psi less than mfr. recommendation for solid ground work on mild steep areas,
but I did not ask too see his engineer degree

buickanddeere · Mar 24, 2015

Did you know that tires are inflated to be max when chaining machinery down for transport from the factory? Do you really think that bubba at the local shop knows more about tires than the engineers who designed and tested the tires ? Drive across some dry concrete with wet tires and you will see all the ground contact area and traction lost. Higher inflated tires also Ride harder.

ovrszd · Mar 24, 2015

buickanddeere said:
Did you know that tires are inflated to be max when chaining machinery down for transport from the factory? Do you really think that bubba at the local shop knows more about tires than the engineers who designed and tested the tires ? Drive across some dry concrete with wet tires and you will see all the ground contact area and traction lost. Higher inflated tires also Ride harder.

As the OP and I have both said, we aren't too concerned with what happens on flat concrete. Now if we were only roading our tractors down the hiway, that might be a valid concern.

I can understand finding different tire pressures on the new tractor lot. Some dealers do nothing to dealer prep their new stock until it is sold. At that time I'm sure all of their checklists include checking tire pressure. What they do about that requirement is left to them. But regardless, I'll adjust my pressure to fit my needs.

My Brother ran Rimguard in all 4 of his tires. He also ran low pressure to gain all that flexible traction that keeps being mentioned. Twice he pushed a front tire off the rim, dumping his Rimguard. After the 2nd time he didn't refill and he increased his tire pressure.

Again, each person's application is different. That reason is why I pay little attention to mfr's recommended pressure ratings other than to not exceed their maximum.