Tyre inflation pressures

Hi this might seem like a pretty obvious query, But I am new to FULL SIZE 4x4 vehicles.
I have just aquired a 1998 Nissan Patrol cab chassis 4.2 diesel, with a steel and timber tray. The tyres that are on it seem OK for hiway use the "Name" is ALL COUNTRY RADIAL LXT. The Numbers on the tyres are 31x10.5 50 R 15.
What I really need to know is what pressure I should have in them, I only carry light loads in the back, camping gear mostly.
Sorry if this seems a dumb question but it once was said " There is no such thing as a dumb question only dumb answers !"

G/day mate & yeah there is no dumb Q:s here...

As a rule most run there 31/10s at 40psi it seems to work well in most cases. If you have a look on your tyre sidewall it should have a recommended tyre pressure for the tyres, other than that there is a thing called "the 4 pound rule" there is something printed up on it here but I can't seem to find it but im sure you could find something on it somewhere.

Thanks for that. I will start out at 40psi and see where I go from there. Dont know what is in them at the moment but the rears look sort of Flat

I'm pretty sure this is what Paul ( patch697 ) was referring 2, if not it might be only a dumb answer :)

Inflation and the 4 psi rule

Tyre pressures vary for every vehicle and caravan depending on weight loads, size etc. An easy do-it-yourself method for checking you have the correct tyre pressure for your vehicle and caravan is known as the "4 psi rule".

Firstly you need to inflate all tyres to the pressure recommended by the manufacturer, for a "cold tyre" reading and then tow your caravan for say a distance of 100 klm on bitumen.

Upon stopping, immediately recheck your tyre pressure while the tyre is still warm.

If your tyre pressure reading is greater than 4 psi from the "cold tyre" reading you took at the beginning of your trip, then the tyres are getting too hot and your starting tyre pressure was too low. Under inflated tyres wear unevenly and lead to increased fuel consumption. They can also impair the handling of the vehicle in the areas of braking and handling.

If the tyre pressure reading is less than 4 psi from the "cold tyre" reading you took at the beginning of your trip, then your starting tyre pressure was too high. You will need to run the test again (once the tyre has completely cooled) with less pressure until you find the right balance.

It is acceptable for larger 4WD's to have a 6 psi difference between the pressure at the commencement of the trip, and after 100 klm of travel.

Remember to use the same accurate gauge for all pressure readings and always carry a gauge with you when possible.


Here is the thread i found it in: http://www.nissanpatrol.com.au/forum...ighlight=pound

Cheers

Todd

Thanks for the link Todd. After reading all that I reckon I will still start out at 40psi and see how it goes
Cheers
Ron

Hey Norplane,i know how you feel. I just bought a 98 Patrol and am going through the process of trying to learn everything i can. Oddly enough, i also live in Caboolture.

I've always run about 32-35, but after reading this I'll check how I go witht he 4psi rule. My logic is that a lot of the roads here are unsealed and depending on the time of year / mood of the last council workers to "fix" it the surface can be pretty rough