Community Forums

Mario 2023 · 06-01-2023, 09:38 AM

I'm new to RVing, I have a 2022 Winnebago 31B Class A and I installed a TPMS to check my tire pressure when travelling. A few weeks ago I went on a 2-1/2 hr trip, it was about 85F and the rire pressure was close to 82psi when I set out. After 2 hours I had 2 tires that showed over 90 psi and the temperature was 105F. I had the RV weighed and I'm below the rated weights by over 300 lbs. I read up on this and thought nitrogen would be a solution but apparently it would not help much. I also read that it's possible that when the tires were filled there was excessive moisture and this could cause tire pressure to rise more than the expected 1psi per 10degF rise. If anyone has suggestions or experience with this I would like your feedback. I'm planning a long trip in July and don't want any problems with a possible tire blow-out.

twinboat · 06-01-2023, 09:50 AM

It's normal for pressure to climb when tires heat up.

The lower the psi below the placard listed psi, the more the tire will heat and get a pressure rise.

Tires blow out from UNDER inflation not over inflation. Under inflation causes sidewall flex and heat, causing damage.

Arch Hoagland · 06-01-2023, 10:11 AM

Were the two tires that heated up getting full sunlight as you travelled?

Mario 2023 · 06-01-2023, 10:29 AM

No, actually, one was the inner tire of the rear duals

Crasher · 06-01-2023, 10:58 AM

All is normal. The inner tires do not get as much cooling airflow as the outers and steer tires do. If your cold pressures are at the placard pressures or at least a few psi above what the load inflation chart states for the weight on each tire, a 15-20% rise in pressure is normal on a day that shows a 20 degree increase in ambient temps. That is the response I got from a Michelin tech 10 years ago. I figured he knew more about tire temps and pressures than I did.

Edit: Did you read this? https://www.irv2.com/forums/f258/new...v2-201159.html

If not, do yourself a favor and reference it for most of your questions.

NCC-1701A · 06-01-2023, 06:46 PM

Nitrogen makes up 78% of the air, so 100% nitrogen does little for tires as the majority of "normal" air is nitrogen anyway.

Not sure where the info you have of one psi increase per 10 degrees F came from. I believe Roger Marble (tire engineer and writer for RVTravel & his own tire safety blog) quotes 2 PERCENT change per 10 degrees F. A percent change makes more sense than a fixed psi change since various tires start with varying levels of PSI at ambient and would not change by a fixed PSI equally..

If your TPMS is on the valve stem keep in mind that your senders probably aren't reading the internal tire temperature accurately. You are getting the temp at the valve stem.