Correct Tire Pressure

dgcarlson wrote:
Jaditir, I wasn't able to use your spreadsheet, so will provide the GAWR for front/rear. They are:

GAWR Front 6000
GAWR Rear 7000

Again the Michelin tires I have are rated as:
275/70 R18 LTX A T2
service Description 125
Load Range E
10-ply
Inflation 80 psi 3640 pounds total load

Thanks to you and all others who chimed in with excellent discussion. I will very likely go with 80 psi cold.

Dave

Filled the data in my calculator and what was striking , is that you have a large reserve in your gawr's of 13000lbs together compared to the GVWR of 10000 you already gave in your opening post.
So I had to fill in asumed axle weights of 4500 front and 6000 back so a little overloaded.
Advice then 53psi front and 72psi rear.
this is for on road tires , if you have off road kind of tires they have smaller sidewall part to deflect and the pressures must be higher
( is my own conclusion of an Ford/firestone article of capri-racer).
But also the axle-loads I used are discussable, as long as you dont know them exactly we keep quessing.
But here a picture of the filled in spreadsheet, mind also the additional informations beneath the pressure-advices.

If your front weight apears to be 6000 you can use the behind advice for that.

I also give a picture of a part of my pressure/loadcapacity list for your tires with the other P/LC so if you have weighed you can use that , but first ad a reserve to the weighed loads of 10% before searching the needed pressure. it is given per axle so 2 tires, so you dont have to devide by 2 first.



So end conclusion is that it all depends on the real loads on the axles, or better even seperate tires. Also the kind of tire can be giving higher maximum load then it can have by laws of nature.
And those laws of nature go above laws of tire-makers and country's.
They punish with tire failure.