Re: Tire pressures

Posted by Fish'n Jim On 2022/12/26 15:15:17

It's a little more complicated than what's been described as the "load" has to be considered as well. The tire's max. rating is at full load which is under the load range letter. You can put your car on a vehicle scale and measure the front and back load. The sum of all your tire max loads should be higher than the GVW.
You can google "tire dynamics" and see all the different things that go into it.
As for wear, there's the cars alignment to be considered. ie, if it's proper or not.
My rule is to check TP if the temperature falls or goes up by more than 20F (~10C) suddenly to make sure at a good value. Usually, that's only about twice a year in the spring and fall. Also before long trip, etc.
Too low and you'll risk flexing the bead and losing the bond and losing pressure and/or blowing out. Not what you want in a high speed turn where the tire is most flexed. I'd not go below about 28 psig front for that reason. Most cars are front heavy, too. This is a common cause of crashes and why the TPMS law came about. If it's not a heavy car, the wear won't be affected as much with a few psi. I've had to run as high as 85 psig(max) in some of my tires to get them to wear flat. Regular rotation is another factor here.
Really go nuts and put a TPMS on your P and get warned. I hate that law. The sensors aren't that robust and they go bad and rather expensive and you have to demount the tire to change. My truck tires are correct but the fault light/alarm goes off all the time and you have to take to the dealer or tire place to reset or have fixed since you can't shut it off yourself. More headache than it's worth. In 12 years, I've only seen that thing work right once. Had a slow leak from a nail puncture.