Continental Tires PSI rising 20

[SGTJOE]

I recently bought Continental 255/70R 22.5's for my Tradewinds, it has always ran Michelins but none were available. I'm traveling from Southern Utah to Southern Arizona and am running 100psi in all 6 tires. I have a TST TPMS that I've used since TST first started that monitors each tires temperature and psi. The 100psi goes up to 120psi going down the road at 65mph. Outside Temps were running high 50's/60's. The Michelins never went up this much. I don't think they ever went more then 6-8 psi, even in 108 outside temperatures. My Honda CRV tow vehicle only gains 2 to 4 psi and these are with Continentals also. My old Michelins were 14 ply and the new Continentals are 16 ply, could this be the cause???

Is there anyone on here who is running the same size Continentals with a Tire Pressure Monitor System that monitors PSI and Tire Temps?? One more thing my Tire temperatures were running a few degrees above the outside temps. The tires were not hot at all, only problem is the 20 degree rise of the psi

[DrewE]

Pressure increase is directly related to the air temperature (and the outside air pressure); it's a simple matter of physics and has nothing to do with the brand of tire. Assuming basically dry air, it very nearly obeys the ideal gas law. Water vapor causes some deviations from the ideal behavior as at typical tire temperatures and pressures water doesn't quite respond as an ideal gas. Maybe the air you have in the tires isn't particularly dry.

If you've driven up a mountain, the increase in altitude will cause a small increase in measured tire pressure since the atmospheric pressure goes down a bit. It's not a huge difference, less than 5 psi for any road you're likely to encounter.

[olfarmer]

WOW, 20 psi gain
seems too much to me at those low temperatures! I don't have an answer to your problem but good luck figuring it out! I would definitely check the tires with a reliable gauge and if the readings are correct I would call the tire company for support!

[MountainAir05]

quick way to see if they in deed go that high is check cold and once they are hot, pull over and check them manual. My only go up 4 max but not your brand. They are Michelin.

[lryrob9301]

NO, the temperature increase you are seeing is perfectly normal. Your Michelins did the same you just don't remember. All motorhome tires will build air pressure as they run down the road some a little more than others due to tread resistance and side wall construction.