Originally Posted by geeman789
Pressure drop is roughly 1 psi per 1 * C ... with a 40*C differential, you should be up at 41 psi garage pressure . At 36 psi garage, you are likely around 28 or 29 psi ambient. TPMS typically triggers at 25 % below recommended pressure, so about 26 psi.
The rule I've heard is closer to 1 psi per delta T of 10 F. Your mention of 1 psi per 1 C would mean a 40 PSI differential, whereas you're quoting an 8 PSI change (which isn't absurd in the least), since that would be 1 PSI per 5 C, which, again, is certainly not absurd.
My compensation does work, and my TPMS will actually kick off around 30 PSI; it's extremely finnicky. Now, with my compensation, if I hit -40 or colder (and it did happen this winter, as you're aware), I'll get a warning. I think the highest I ever set it to in garage was around 39, not that 41 would be silly or out of the question, either. If I set it at 33 PSI on the hottest day of the summer, I get TPMS warnings long before a real winter day appears, at least by our standards. I don't mind the Infiniti's TPMS being as picky as it is. At least it's useful!
Overkill: My god daughter's Benz has two sets of pressures as well. Her TPMS was bothering her as well, since it was set indoors in a shop at a warm temperature, and then our February came. I set it to the German pressures, and the problem disappeared.
Oh, to make matters worse, her tires were about finished in February, and she ran something over, got a flat, and had no spare. It was -30 and she was so happy, too!