Tire Pressure? 31x10.5

[Stoeger]

I just got a set of 31x10.5 and the guys at the tire store said I should run a higher PSI than "normal sized" tires.

They recommend 40-45 PSI.... is that right?

[cc_Penguin]

I'd just check the side of the tire, and put in what 'it' stated... If memory serves correctly though, 40-45 sounds about right.

[csparks78]

Originally Posted by Stoeger

I just got a set of 31x10.5 and the guys at the tire store said I should run a higher PSI than "normal sized" tires.

They recommend 40-45 PSI.... is that right?

Go by what your tire is rated at, mine is 50 psi also 31 10.5's. I have never heard that unless they were just trying to give you a heads up so if they are rated at 50psi you weren't putting them at the "normal" 35. You don't want to go over what it says because you will get center tire wear

[Ray H]

I run 32PSI in my wifes 31X10.50s on her TJ.
Dont go by the pressure rating on the side. That is the recommended maximum pressure and is rated high to accommodate much heavier vehicles than your Jeep.
The guy at the tire store is full of it. When you go up to a larger tire, you should run less pressure than you did with a smaller tire. A larger tire has more square inches of contact on the road so it requires less pounds per square inch to support the same weight vehicle. Heres an extreme case but think of the difference between a bicycle tire with 70PSI verses an ATV with 5PSI.
Heres some info on tire sidewall markings.
http://www.tirerack.com/tires/tirete....jsp?techid=21

[csparks78]

Originally Posted by Ray H

I run 32PSI in my wifes 31X10.50s on her TJ.
Dont go by the pressure rating on the side. That is the recommended maximum pressure and is rated high to accommodate much heavier vehicles than your Jeep.
The guy at the tire store is full of it. When you go up to a larger tire, you should run less pressure than you did with a smaller tire. A larger tire has more square inches of contact on the road so it requires less pounds per square inch to support the same weight vehicle. Heres an extreme case but think of the difference between a bicycle tire with 70PSI verses an ATV with 5PSI.
Heres some info on tire sidewall markings.
http://www.tirerack.com/tires/tirete....jsp?techid=21

Wow!! Learn something new every day I did not know that but It makes sence and I will be airing my tires down!!! Thanks Ray and sorry about the bad advice Stoeger!!

[Stoeger]

Thanks Guys, I think I'm going to air down to 35 and see if that helps... I think it will. My Tire Marking says 50 PSI *MAX* but I think sweet spot will be much less than that. Check out this link, this guy seems to be happy with 22PSI on the highway! (Seems low to me, but maybe like you said, maybe the big tire supports the weight just fine!?!?) Very interesting...... http://www.4x4wire.com/mitsubishi/reviews/yoko_geos/

[fredjacksonsan]

I've found that the tire pressure you run depends on the weight of the vehicle. There are a couple of ways to determine if you are running the right pressure.

After about 5K miles on the new tires, check the wear pattern. If worn at the edges, pressure is too low. Worn in center? Pressure too high.

Of course you could always do the Road & Track method used for sports cars, and peel out in order to leave some rubber on the road; you're looking for a dark mark the entire width of the wheel, even colored across the entire width. This might not be feasible with oversized tires.