Tyre Pressure

[Tom63]

Sorry I know this has been covered before, but i can't seem to find the pressure for my tyre size, they are 31x10.5x15 firestone AT it says on the wall 50 psi max load, but what is the optimum running pressure for this tyre ?
Thanks for the help.

[NiftyNev]

I have same size but different brand of tyre.I run them at 36 PSI.There is a formula for working out correct tyre pressure.I think they call it the 4 PSI something or other.

It works like this I believe.Inflate tyres to a certain PSI when cold.Lets say 34 PSI.Drive the vehicle until tyres have reached operating temperature then check pressure again.If they are now at 38 PSI then the original pressure is correct.If pressure has risen more than 4 PSI then you need to raise original pressure.If pressure has risen less than 4 PSI then you need to lower original pressure.

I think it may have been Pirelli that published this somewhere.A search on the net may this.Must see if I can find this as well.

Neville

[Linda]

I run the same size A/T's but not firestone - usually use 31psi, but lower them a bit off road.

[Tom63]

Thanks Guys

Thanks for the advice guys I will giv it a go.

MERRY CHRISTMAS..........