so the jeep we just bought has some 31-12.50-15 pro comp tires. what would be the proper air pressure to run the tires at for a daily driver? I suspect that they are way over inflated, as they hum pretty bad for an all terrain and they look it. Once the son gets home I will verify the pressure and post it up. I was just wondering what you all run for pressure to preserve good wear on the road with a daily drive?

 

What size wheel are they on?

 

draw a line of chalf from the inside to outside of the tire. if the center wears faster, theres too much pressure. if the outside wears faster, too little. you want the line to wear evenly across the tread.

the "ideal" pressure is different for every tire/wheel/rig/weight/offset combination.

 

You again? LOL


Spot on. There is not one correct answer for every tire.


One way to do it somewhat is to wet your tire, drive several feet and look at the pattern. As already said, you want even wear.

 

16 inch wheels. they were 49psi each

 

Your first post says the tires are 31x12.50x15s I ask what size wheel and you say 16". I'm hoping one of your post is wrong. If it's a 15x16 wheel with a 12.50 tire I'm not sure how you set the bead and if it's a 15" tire on a 16" wheel I'm not quite sure how you did that either.

 

Maybe he made a typo but the chalk way is the best way to get it prefect.

 

Wow....49 is a lot.

Getting it "perfect" will require the chalk or water test above. But generally, XJ's tend to be around 32 PSI on the street. I have never tested mine and have no wear issues that bother me, and I run 30-32. That was with 31s, 33's and 35inch tires.

Some people may take it way up to get slightly improved MPG despite the ill effects...

Anyway, you want the best possible wear, do some testing. Or just put it about 32 and don't worry about it, like most people

 

Put whatever pressure it takes to wear the tires evenly. There is not one specific pressure that works for everybody. My 33's only took 18 psi to wear evenly.

 

Yea chalk. Autocorrect blows

 

Yea chalk. Autocorrect blows

 

sorry, was a typo, they are 31-12.50-16

 

if stock size requires around 32psi and 33's run smooth with around 26, then i'd go somewhere inbetween.