Originally Posted By: gaijinnv
Originally Posted By: aztec12
most truck or suv's tires say max pressure 44 psi.But as far as I know any shop will only inflate them to 35 psi, is that the average or why?
Every vehicle is required to have a sticker like this one on the Driver's side door jamb:
It tells you the wheel size, tire size and tire pressure recommended by the manufacturer for best compromise between comfort, performance, mileage and safety. These recommended pressures are the result of extensive testing by the manufacturer and are to be ignored at one's own peril.
Also note that the tire pressures are measured when the tires are "cold," i.e. after the vehicle has sat for several hours, the tires are not in the sun, and the ambient temperature is close to what will be experienced when driving.
As mentioned by others, the maximum inflation pressure embossed on the tire sidewall has nothing to do with what should be used for normal driving.
Really?
Aren't those pressures listed the minimum pressure required to carry the maximum weights the vehicle is rated to carry? And, you have to read the fine print on the tire's sidewall to find what the pressure number there means. It might be the max cold inflation pressure that tire should ever have, or in the case of LT tires it is the minimum pressure required to carry the max weight that tire can carry, and up to 10 psi more is OK.
There will be another sticker on the door jam, or inside the console lid, or inside the gas filler cover that gives the recommended pressures for everyday driving. For a truck these might be the same just so you don't carry a heavy load with tires inflated for a light load.
So...what pressure should we run? Start with the cold inflation pressure on that sticker. Try increasing the pressure a couple of psi at a time until you find what feels best for you. I stay real close to the sticker pressure except when I have a full pick up load (or overload) of landscape materials or building materials. Then it's up to the sidewall max only for that trip, or when towing a heavy trailer and I want the added stability of the firmer tire. I do like the feel of two or three psi more in the fronts to reduce understeer.