tyre pressue

brianr70 · Post by **brianr70** » Fri Dec 29, 2006 12:58 pm

can anyone advise the correct 'everyday' tyre pressure for 31x10.5x15 Firestone RMT Tyre????? Ta

wjw · Post by **wjw** » Fri Dec 29, 2006 1:04 pm

I always ran them at 32psi..

icekayak · Post by **icekayak** » Fri Dec 29, 2006 5:23 pm

I think it depends on the vehicle (ie weight), like i normally run my Pirelli 31" Muds at around 25psi (it says 23 on the door of the car) but that's on a zook

4WDbits · Post by **4WDbits** » Wed Jan 03, 2007 2:34 pm

One school of thought is to use the max load @ pressure markings on the tyre sidewall, work out what percentage of max weight you have on the tyre and use that percentage of the max load pressure (does that make sense).
ie max load @ pressure marking on tyre (BFG 315/75R16 in this case) is 1450kg @ 50psi. If you figure you have 870kg on the tyre (60% of max load) then run it at 30psi (60% of 50psi).
Remember that a tyre 10% under infalted has much less grip on the road than a tyre 10% over inflated.

warlord225 · Post by **warlord225** » Wed Jan 03, 2007 2:40 pm

if its a bigger vehicle, around 36psi.
medium 34psi
small 32psi.
suzuki about 25psi

icekayak · Post by **icekayak** » Wed Jan 03, 2007 3:24 pm

4WDbits wrote:One school of thought is to use the max load @ pressure markings on the tyre sidewall, work out what percentage of max weight you have on the tyre and use that percentage of the max load pressure (does that make sense).
ie max load @ pressure marking on tyre (BFG 315/75R16 in this case) is 1450kg @ 50psi. If you figure you have 870kg on the tyre (60% of max load) then run it at 30psi (60% of 50psi).
Remember that a tyre 10% under infalted has much less grip on the road than a tyre 10% over inflated.

I should find out what my zook actually weighs then...
Tyres are 2100lbs @ 50psi each (from memory)
The net says the curb weight is 2332lbs
so assuming the weight is evenly over the four tyres thats 582lbs in each tyre (and 28% of max load), therefore i should be running them at around 14 psi

Jerry · Post by **Jerry** » Wed Jan 03, 2007 3:39 pm

There shoud be a sticker on the drivers door which says what they should be run at. the Rugger says 26 and the Grand Vitara says 28, interestingly the Tonys sticker says 40 !!!, these are all road pressures, I normally drop these to 20 or 15 depending on the trip.

callum007 · Post by **callum007** » Wed Jan 03, 2007 9:35 pm

my van i run at 55. ran truck today at 3..

xj · Post by xj » Wed Jan 03, 2007 10:03 pm

normally run 45 on the road, oh and shit..... had 45 odd in em today too........ noooowwwww...... i wonder.............