Captain Coop

I just had 35" Cooper STT tires put on the truck When the guy put them on I asked him what pressure he used. He said 35 PSI. Is this ok. The tire has a maximum of 50. I dont tow much just do a lot of highway driving so I was just wondering if maybe a little more tire pressure would help the life of the tires. I figured I could just air down a little when I want to go in the mud or something.


Also, the truck is pulling to the left pretty good now. Is this something that I could easily fix on my own through trial and error or should i just go have it aligned.
Thanks in advance for the help.

Beast2B

as far as pressure (37-13.50-17 Toyo M/T) I run 28 in the rear and 50 up front unloaded. I'll go to 50 in the rear if I'm gonna tow the big trailer. It depends what you want: max tire life, max firm handling, best mpg... I came to these settings by running the truck for a few days and looking at the tread. If the tires are over-inflated you'll see a bare strip on the outer edge of the tires where the tread is not running on the ground. After I found a pressure that caused this strip to show, I back the pressure down until the tire tread was flat on the ground. I got 50k out of my 37" BFG mudders and I'm around 20k on the Toyos with a bunch of tread left. Best mpg = max pressure, but you'll wear the tires unevenly so think the savings in fuel is a moot point...
remember, just my $0.02!!

1882

I run Cooper STT 35's and 50 psi is perfect for wear, mileage and preformance. This is only a D load rated tire and E is the standard so you'll want to be at the max psi due to it being a lesser load rated tire. 50 psi it is!

Busboy

If you take the max load the tire can carry say 3000lb and divide it by the max inflation pressure say 50 psi 50/3000 = 60 then multiply by the pressure you are running at, say 35psi. 60 x35= 2100. so at 35 psi each tire can carry 2100 lbs.

JohnX

So since the rear axle on my truck scales at 2200 lbs empty, I can run about 18psi in each rear tire??? While your theory is good, there is a minimum recommended pressure most of the time.

Nick02Ram

I've always run my tires about 5 psi below what the sidewall says, always gotten pretty good wear out of em. We do the same @ work with semi tires. However, with OEM car and LT tires (same size and brand as stock) I inflate to what it says on the door panel.

Busboy

All those numbers were hypothetical just to show how tire shops calculate how much load a specific tire can carry at a given pressure. As you know all vehicles have a placard that states what pressure and size of tire should be used.

Captain Coop

Cool. Thanks for the help. i upped the pressure today to about 47 PSI. Im gona see how that does tomorow i have to drive 400 miles. But I like it so far.

JohnX

Yeah, I know. I was just bustin your ***** a little.