tire psi question, need help on recommended tire PSI


Jan 7, 2018
I replaced the 255/40r19 Pirellis with the 96w rating with Cooper 255/40r19 with the 100W XL tires, the tire shop i think overinflated the tires. one of the tires read 40 PSI. I know my stock tires were recommended at 32 PSI cold. Do you think the Cooper's being XL load range 100W that the correct tire pressure is 40 PSI, or is that too high? I can't get reliable information because the 96W and 100W XL would probably have different PSI recommendations, right ? Then I read, if you under-inflated the tires, they go bad fast, over-inflate them, they get punctures easier.
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Honey, I need a check for $30k to pay the hooker
10 Year Member
Apr 20, 2010
SW Michigan
Somewhere on the side of the tire, it will say what to inflate it to. Something along the line of "xx max psi cold"

I Bleed Ford Blue

Well-Known Member
Feb 13, 2017
North Olmsted OH
The tire pressure on the tire itself is the max pressure the tire is designed to handle. The 96 and the 100 rating is for tire wear, the higher the number the better. The XL is extra load, meaning the tire has more belts or plys and can handle a heavier load. The sticker on the door jamb is what you should use. All manufacturers calculate the optimum tire pressure based on weight of the vehicle and tire width. As long as you stay with the same width tire then use the manufacturers recommended tire pressure. Now you can play with the pressures a little to improve traction or mileage, but don't go more than 2 or 3 psi away from what ford recommends. Beyond that you start to increase uneven tire wear.