Am I running the wrong psi?

[Gavidoc]

I did some searching but have come up empty. Could use some help.

Bought my TJ a few years ago and it came with a 3” lift and some wrangler duratrac 285/70r17 D rating. I drove it home on I-90 and was bouncing all over. When I checked the psi the previous owner had it set to 35. Lowered it to 28 and they’ve driven much better but for some reason I’m questioning if that is the correct PSI.

Any assistance would be appreciated.

Is 28psi correct for the tires?

 

[AndyG]

I did some searchin but have come up empty. Could use some help.

Bought my TJ a few years ago and it came with a 3” lift and some wrangler duratrac 285/70r17 D rating. I drove it home on I-90 and was bouncing all over. When I checked the psi the previous owner had it set to 35. Lowered it to 28 and they’ve driven much better but for some reason I’m questioning if that is the correct PSI.

Any assistance would be appreciated.

Is 28psi correct for the tires?

Yes it is. We’ve been allowing owners to run 28 psi, And we can even get you special permission to run as low as 26 PSI, provided you have proper tread depth and the tires meet forum guidelines.

 

[Gavidoc]

Yes it is. We’ve been allowing owners to run 28 psi, And we can even get you special permission to run as low as 26 PSI, provided you have proper tread depth and the tires meet forum guidelines.

Lol. Thanks boss.

 

[L J]

Yes it is. We’ve been allowing owners to run 28 psi, And we can even get you special permission to run as low as 26 PSI, provided you have proper tread depth and the tires meet forum guidelines.

he will also have to run a placard for safety

 

[deeptread]

I'm running 24 psi on 305/70/r16 BFG T/A load E. Swapping out these PO selects to load C when these are done.

 

[Bobohunter1776]

Yes it is. We’ve been allowing owners to run 28 psi, And we can even get you special permission to run as low as 26 PSI, provided you have proper tread depth and the tires meet forum guidelines.

B-b-but the sidewalls are gonna overheat and explode and you're gonna hit a bus full of nuns!

 

[Kenneth G Zinis]

With my 33 x 12.5 x 15s, I find 27 (cold) is good. Try chalk test to see your contact patch.

 

[MikekiM]

With my 33 x 12.5 x 15s, I find 27 (cold) is good. Try chalk test to see your contact patch.

Same here. Wild Peak AT3W in the same size.

I dropped tire pressure from mid-thirties, where the the OP had it, to 26-28 psi and use the chalk test to confirm.

 

[Jerry Bransford]

With my 33 x 12.5 x 15s, I find 27 (cold) is good. Try chalk test to see your contact patch.

X2. Personally I like 26 psi for 33's for when the TJ is lightly loaded and 28 psi when it's fully loaded with people and/or gear.

I'm not a fan of the chalk test as it can result in severely underinflated tires when performed by those who don't know what an acceptable pressure is/is not. Some think the chalk has to come off the entire tread but the edges of the tread are usually not supposed to be in contact with the road except during hard cornering or when they're aired down for offroad use.

 

[deadbeat son]

I did some searching but have come up empty. Could use some help.

Bought my TJ a few years ago and it came with a 3” lift and some wrangler duratrac 285/70r17 D rating. I drove it home on I-90 and was bouncing all over. When I checked the psi the previous owner had it set to 35. Lowered it to 28 and they’ve driven much better but for some reason I’m questioning if that is the correct PSI.

Any assistance would be appreciated.

Is 28psi correct for the tires?

It’s important to remember that larger tires require less pressure to carry the same load (weight). You can verify with a load inflation chart. The factory sticker for my TJ with OEM 30x9.50R15 tires specifies 29psi. So yes, 28, or even slightly less as has been recommended, is safe.

 

[Claybirdd]

24 psi for my 35x12.5x15's.

 

[AndyG]

he will also have to run a placard for safety
View attachment 433037

Chris I like the way this guy thinks. Let’s watch him.

 

[AndyG]

All good posts. Especially mine.

 

[Woodrow]

I’ve been running 24psi in load C 33x12.5x15 on 8” wide rims for several years. I’m getting even wear and a good ride and road handling. Last week in Moab, I drove around at 10.5psi with the swayloc in off road mode all week and the ride was really good. No nuns were injured.

 

[MikekiM]

I’ve been running 24psi in load C 33x12.5x15 on 8” wide rims for several years. I’m getting even wear and a good ride and road handling. Last week in Moab, I drove around at 10.5psi with the swayloc in off road mode all week and the ride was really good. No nuns were injured.

Pictures from Moab?
Nuns are optional.

 

[Woodrow]

Pictures from Moab?
Nuns are optional.

Coming in my build thread in the next few days. It was the 1st big outing for the original build concept. Need some time to organize and get settled at home then do a hopefully thoughtful review of the build.
There will be no nuns.

 

[OldBuzzard]

Oh yes there will:

 

[txbemis69]

running 24 psi. on 33X12.5X15. seem to be wearing evenly.

 

[williambmac]

B-b-but the sidewalls are gonna overheat and explode and you're gonna hit a bus full of nuns!

That's only on Ford Explorers.

 

[bucky]

The pressure number on the side wall if for maximum load capacity. My tires are load range E. They will never see that kind of load on a TJ. IMO you can air down a tire until it will not hold the bead or the side wall flex is too much as to cause excessive heat build up or stability issues both of which increase with speed. On my F250 I run my Load range E tires at 45psi and only put them at 80psi when I carry a large load or pull a heavy trailer. One other advantage of running off road at a lower pressure is the side wall has some give when encountering a rock.
The Explorer issue was that people let the pressure get too low causing excessive heat build up and subsequent tire failure. Then the dumbasses slammed on the brakes causing loss of control. Ever watch a high speed chase? They hit a curb blow a tire and keep on going until they are running on the rim. Why do they not lose control right away? Because they don’t slam on the brakes. Take your foot off the gas and slowly apply the brakes.