Tire pressure advice

Rebel_Frontier

New member
So I'm running 31x10xR15's right now. Just got them actually; Goodyear Wrangler Authority A/T's. My question is, what psi should I be running them at? Might sound like a noob question hah but I just want to be sure.
 

Just for road use? Or are you doing everything?
 
Basically road use. The only offroading around here is mud and sand. So if you'd like to throw recommended psi for that as well be my guest.
 
I run my Authority's at 30psi I've got 20k miles on mine with minimal wear(all street miles)...
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Chalk the tires and drive a circle in a parking lot. Your looking the max pressure and still have 100% of the chalk whiped off the tire. Change by 1psi increments.

You will also find a difference in pressures front to rear.
 
Jeeps don't weigh a lot compared to other vehicles that run the same size tires. Rim width matters too, a wider rim will require a little more air. I run 235/75-15's on OE aluminum wheels (that I bought later) and they seem to wear best at 26 psi. For 31's I'd start with 26 if you have 7" wheels and 28 if you have 8" wheels and see how it goes.

For 'froading in mud I wouldn't drop the air pressure because you don't want the tread to close up or mud to get into the bead and cause a leak. For sand I would drop it to around 15 psi.
 

30 psi? Isn't that low? Mine are running at 37 right now lol

Smaller stock tires only need 33psi, bigger tires require less air to hold the same load...

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My "certified mechanic" friend thinks that 15 psi for sand is way too low. He won't drop the fact that no one on here knows what they're doing.
 

Tell your friend that I have been stuck in the sand before at full tire psi and had to start dropping psi to try and get unstuck, went down to 10 before it would pull itself free. I run my 33,s on the street at 30 and I feel that is just a bit too much for mine. For your 31,s I would think in the area of 27-30psi would be fine.
 
Tell your friend that I have been stuck in the sand before at full tire psi and had to start dropping psi to try and get unstuck, went down to 10 before it would pull itself free. I run my 33,s on the street at 30 and I feel that is just a bit too much for mine. For your 31,s I would think in the area of 27-30psi would be fine.

Cool :) thanks guys
 

Chalk the tires and drive a circle in a parking lot. Your looking the max pressure and still have 100% of the chalk whiped off the tire. Change by 1psi increments.

You will also find a difference in pressures front to rear.

This!
 
Chalk the run surface. The part that hits the road. Slow,very slow, big circles stopping often the first time to see when the chalk rubs off. This will show you your wear pattern. You want an even chalk removal straight across the tire.
 

Draw a thick chalk line across your tire. Drive a few tire rotations and look at the chalk. proper pressure should show even chalk removal. FYI you should not be below 20 psi when complete. This considers you have sufficient wheel width for the tire width. Running 13 in wide tires on 8 in rims will cause the tire to bulge and the chalk test will result in pressure too low.
So I see you have 10 in wide tires? What is your wheel width?

Lots of tire info:http://www.4crawler.com/Diesel/Tires.shtml#ProperInflation
 
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When I go mudding (without tire chains, that is), I usually drop my air pressure to 15 PSI. For sand, I usually go to 10 PSI. On the road, I tend to go to around 25, but for long trips, I increase the pressure to reduce the rolling resistance (hence reducing the fuel consumption). But for every day driving, there is no better method than the chalk already mentioned to find the correct pressure (to insure proper wear on the tires).
 
I run 32 psi on the road and drop it til the sidewall flexes good in the slick. Not sure what that magic number is, just know it when I see it. I've got 33" BFG's at's on 10" rims and who knows when it was aligned last. They seem to be doing well, no wear that I've seen.

Tell your friend... well I'm sure he already knows.
 

I ran my 31" BFG ATs on my TJ at 29 after doing the chalk test. I was at 50,000 miles of running it like that when I sold it and it was wearing pretty evenly.
 
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