tire pressure question

What pressure should I be running in my tires 31x10.50 M/T for on road driving.

it should say on the tire i run 30 but mine tires are 35 bias ply baja claws

What it says on the tire is the pressure for maximum load, which you don't have anywhere close to on an XJ. If you're running 30 on a set of bias ply 35's you're probably running too much.

The corrent tire pressure is whatever it takes to have a full tread foot print on the ground. If you don't see evidence of the tire hitting the ground all the way to the edge of the tread, then you have too much air. Use just enough to get full tread contact on the ground, otherwise you'll either wear out the edges from too low or wera out the middle from too much.

For 31's, 30 lbs might be OK. Street presure on my 37's is 22 lbs.

What it says on the tyre is normally the maximum it can run for a given load and temperature. Each tyre of even the same size need a different pressure according to construction, load and conditions. So anyone giving advice to run so many psi will only be a guide as unless load, tyre size, brand and construction plus road and temperature are the same, it wont be exact for someone else.
The best I have found is to use the 4 psi rule. That is where the tyre should increase by 4 psi from cold after a 1/2 hr or more highway run without stops. If you have less, you start temperature was too high and if you had more, it was too low a start temperature.
See my write up for more information. http://www.go.jeep-xj.info/HowtoTyrePSI.htm

cj11 said:

What pressure should I be running in my tires 31x10.50 M/T for on road driving.

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I ran mine at 32 psi for commuting. I run the same psi with my 33s for commuting.

I run my 35" MTRs at 30 psi. It rides well, there's a bit of tire squat weight-on-wheels, and feels like a good psi for my set-up. I may play with a couple of psi either way in the future, but 30 feels about right.

I run 29lbs on my bfg 30". Put chalk across your tire tread and drive the jeep. If there is still chalk left towards the outside of the treads, lower your air pressure. If the middle still has chalk on it raise you air pressure. You'll see when the whole contact patch is touching.

87baseomatic said:

Put chalk across your tire tread and drive the jeep. If there is still chalk left towards the outside of the treads, lower your air pressure. If the middle still has chalk on it raise you air pressure. You'll see when the whole contact patch is touching.

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Exactly

That does not take into account the rise in pressure you get when when driving. So your chalk mark can wear off evenly in the cold test and then find you are over inflated due to the increase in psi once driving.

Gojeep said:

That does not take into account the rise in pressure you get when when driving. So your chalk mark can wear off evenly in the cold test and then find you are over inflated due to the increase in psi once driving.

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solution...go drive for awhile to heat up the tires...stop...chalk it. Drive more...stop...check chalk.