So my truck has a set of Goodyear Wrangler Radials. They are pretty much the cheapest tire available (down to $74.50 a tire at Walmart lol) and only come in the stock 235/75/r15 size. The tires aren't horrible, but they do seem to show their cheapness. I have a question however. All 4 of my tires are marked with a maximum psi of 35. The truck's door sticker is rated higher than that front and back. I have been running them at 32 psi on the front and 29 psi on the back (lower on the back to keep the centers from wearing badly). What should I run them at? Does the 35 max mean that even when the tire is fully hot after driving that the psi should be at or below 35? Or does that mean a max of 35 psi cold? I think maybe tonight Ill fill them to 34 on the front and 31 on the back and then put a line of chalk on each tire and see how they wear.

 

The max rated tire pressure is for max rated tire load, if you don't load the truck often then you don't need to run at max tire pressure, use whatever pressure delivers the most even tire wear.

 

I say just keep it at 35 psi cold and leave it. I however run 45 psi in my tires with no odd wear but thats over what the tires are rated for on my truck. I believe mine is rated for 35 in the front and 45 in the back but i just run it all 45 and the only time you will need 45 in the back is if you are hauling allot of something heavy. I take that gamble because its helped out with gas miledge and rolling resistance some on this truck with the mud grips in the back and the skinny street tires in the front. But like i said before keep it at the cold max and you should not have any issues unless your truck is out of alinement.

 

On the sidewall it generally says max inflation pressure cold, so that's the pressure the tire should be at when cold in order to carry its maximum rated load. The pressure will go up as it warms up, and it can go over the max cold pressure. That's OK, but be reasonable too. Inflating them at 20 below, driving to somewhere it's 120 above and entering a road race is still stupid

Good plan

 

P235/75/15 tires are 4 ply and have a max inflation of 35PSI. LT235/75/15 tires are 6 ply tires and have a max inflation of 50PSI. The latter of the two are the ones your truck would have had from the factory and are the ones your door sticker is referring to for inflation pressures.

 

Generally correct, however there are extra-load P235/75R15s out there rated at 44 PSI. Still won't handle as much punishment as the LT series tire will, but they exist.

Go with what is on the tire, not what's on the door, ask anyone who owned an early 90s Explorer what following Ford's door sticker will get you (there's a reason they're nick-named exploders...). I ran those same Goodyear's on my 76 I used to own and kept them at 35 cold, no wear problems. Yes my 76 was a tad bit heavier, with the slightly heavier 70's body, but not THAT much heavier. Play around with it until it feels good to you, but these things are good riding at 35, dropping the pressure won't help the ride much.

 

Neither is necessarily correct, both give useful information.

The door sticker gives what the vehicle manufacturer thought the tire pressure should be with the original equipment tires and the vehicle carrying some typical load (probably at GVWR for a pickup). That is USUALLY a very good place to be if you are using tires that are the same as the OE tires. The Ford Explorer was a very notable exception where the vehicle manufacturer's recommendation was terrible.

As stated many times in this thread already, what's on the tire is the tire manufacturer recommends for carrying the maximum load the tire is rated to carry. That is always the right pressure to be at if you are carrying at (or anywhere near) the tire's rated load. But it's way too much if you are carrying way under the tires max rated load (anyone running 80 psi in the rear tires of an empty 3/4 ton pickup is a masochist).

All of that said, generally running slightly too much pressure is better than slightly too little, as long as you aren't going over the tire rating. So usually somewhere between what's on the door sticker and what's on the sidewall is good. And with a half ton truck running close to stock tires (like what's being talked about here), the number on the sidewall is probably pretty close.

 

Running them at 34 front/31 rear seemed to wear the chalk away pretty even. Im sure it wouldn't hurt to have a wheel alignment either... but thanks for the info on it guys.