Hi guys...can anyone give me a rough gide of the tyre pressures in p.s.i please for off and on road for .....235/85/16s..and for a set of 31s too please..thanks for any help..all the best,,,wayne.... ..also the tyres on at the mo are bridgestone 235/85/16s ..and they at 50 psi...tyre wall states 80 psi..but that seems a little high to me....

I am assuming without beadlocks??? If so then you don't really want to go any less than 18psi really as the risk will then be of popping a bead, on road would be around 25psi or maybe as high as 30psi. Personal preference on that basis, but it would probably state the correct pressures in the manual etc. But this will also depend on what car it is, 90, rrc, disco etc as they are all different weights

Not knowing the tyres or vehicle it is difficult to give a direct answer. You really need to look at the tyre manufactures figures for the tyres in Q and then using your axle weights get a starting road pressure to work from. Chalk test will help you refine this for road use. How much you drop them by for off road (30% is my starting point) again really depends on conditions and what protection you have to stop the beads coming of the rim.

hi mate,,its a 1990 rrc..tyres are bridgestones...thanks for reply...

hi,,thanks for reply,,,its a 1990 rrc..and the tyres are bridgestones,,on the wall of tyre it recomends cold pressure of 80 psi,,,i thought this was a little high so ive put 50 psi in them but they seem a little wobbly,,and seems to wonder a little on the road...cheers...

I think you will find 80psi is the maximum...
My Iveco van, on 175/75R16s only takes 70psi.

I'm not surprised it's a bit wandery at 50psi, the figure on the sidewall is probably the max safe pressure. I'd expect somewhere between 15 and 35 psi for most LR tyres, lower pressures for bigger/fatter tyres. Stock sort of pressures for on a RRC would be ~28 front ~35 rear, possibly a bit lower.

That 80psi is pressure at max load. It should also show the max load? We just need to factor it down for the typical load you are putting on the tyre, say 600kg per tyre on an RRC.

ok thanks for the replies...id best let a bit a wind out of em them,,lol...ill try 30 in each an go from there as a start..only had the rrc a couple a weeks an the tyres were a bit flat so wasnt too sure wot really to put in em,,the wandering may be due to a worn pair a track rods then by sound of it,,,right thanks for the input guys...cheers again...wayne....