on road tyre pressure

Petemcc · Post by **Petemcc** » Wed Apr 18, 2007 1:34 pm

what pressures do you guys run on road. i have 33x12.5 goodyear wrangler mtrs on my surf and was told by a guy to try running between 40 and 50 psi. have been running about 42 and its going way better. handels better and uses alittle less gas. anythoughts ????

Cheers Pete

Steve_t647 · Post by **Steve_t647** » Wed Apr 18, 2007 3:34 pm

Also decreases the size of the tire patch on the road, just something to be aware of Most mud and 4X4 tires have a huge working pressure range to run over. In wet conditions or slipery conditions on the road you may find you have less grip.

Personal preference but I would check the top of he tire is flat and not curved slightly running that high (flat like a car rather than proud sort of like a motorbike). 40 is past recommended manufacturer tire pressures Goodyear MTR's recommended road pressure is 34-35 PSI.

bigger tires do create more drag thay is why I have 2 sets, also they are so bloody expencive to run all the time 15 - 20 min changing the tires is far cheaper, just not an instant Yip I will go. (Cordless drills are great tools for undoing and doing up the major part of the spinning) :oops:

4WDbits · Post by **4WDbits** » Wed Apr 18, 2007 10:16 pm

2 rules of thumb I've heard, I use a combination of the two myself.

1. Set the pressure to a percentage of the max load/pressure rating for the tyre. ie a tyre with pressure/load of 50psi/700kg with 500kg load, set to 35psi.

2. In semi soft ground adjust the pressure until you get an even impression in the ground across the width of the tyre.

Both have there floors.

Taz · Post by **Taz** » Thu Apr 19, 2007 12:26 am

I run my bridgestones at 50psi because thats what it said on the tire.

How often do you guys check your tire pressure?

TJ · Post by TJ » Thu Apr 19, 2007 1:10 am

I am sure the 50 psi is supposed to be the "max" rating of the tyre, which is stamped on the sidewall. How heavy is your truck? Running constant 50 psi seems very high/odd, unless its a commercial truck of some description carrying heavy load.

I drive a TJ, which is very light (comparatively) and is very happy with 29/30 psi around town. Anything higher and I can feel the road in every bone of my body.

You should try and see what suits your set-up i.e. weight of your truck and the tyre rating. LT tyres are different. What works for someone else may not necessarily work for you. As for checking pressure, I do it pretty much every week and can normally tell the difference in handling if there is a difference between the tyres.

Taz · Post by **Taz** » Thu Apr 19, 2007 1:41 am

Woops! Might let them down a bit next time I take it out

Its a 1994 Nissan Safari, I'm not sure how much it weighs but it drives like a bloody pig so it'd be a fair bit.

IcedJohnno · Post by **IcedJohnno** » Thu Apr 19, 2007 10:32 am

I run my 31 BFG MT's at 40 psi. The 71 series Prado handles way better with the tyres at that pressure. Does not alter the stopping distance either in my experience.

Larger tyres require less pressure for a given load/sidewall deflection as more force is generated due to the larger internal surface area
Force = pressure/area