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Old 04-17-2017, 10:37 PM   #1
Brand: Thor Motor Coach
Model: Hurricane 35M
State: Virginia
Posts: 46
THOR #6664
Expected Tire Pressure Increase

Hi All,

I searched the forum and did not see an answer to my specific question. I have a Hurricane 35M and the recommended cold tire pressure is 95 psi. I have an EEZTire TPMS and when cold, all tires read 95 psi.

When moving down the freeeway, the psi increases to 116- 119 psi. Is this normal? EEZTIre manual had me set the alarm at 114 psi, so it was going off a lot! Best I could discern from the WWW is that as long as all the tires were within 1-3 psi of each other, this was normal.

What do others see? Thanks in advance for your help!


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Old 04-17-2017, 11:12 PM   #2
Senior Member
Brand: Still Looking
State: Alabama
Posts: 245
THOR #4160
I have EEZTire TMPS as well and was just as confused so I contacted Michellin and here is what I got. Of course I have the 22.5 tires so not sure if it would change for the 19.5 tires. Here is the exchange with them, I hope it helps.

Hello Erich,
Thank you for your email. We welcome the opportunity to serve you.

In regards to the email you sent stating:
Thank you for the quick response. If I understand you correctly, spikes between 6-12 PSI are normal. I maintain my tires at 100 PSI, the recommended PSI. I have seen spikes up to 120 PSI when traveling for a long period of time in warm climates. The ultimate question is, under normal driving questions, what is the highest level spike that is acceptable under normal driving conditions with a 100 PSI being maintained as the recommended pressure? Basically, I need to know what to set the TPMS max before the alarms start going off and I need to be concerned?


Spikes between 6-12 psi are normal in normal driving, and weather conditions. Based on your tire information, the max pressure would be 110. The tires should never be initially inflated to anything higher than 110psi, however due to reinforced sidewalls, steel belts,and tread compound the tires are actually able to withstand up to 25-30psi over this max pressure.

If your initial tire pressure asks for 100psi, then your warning level would be at about 125-130psi. When reaching these levels we recommend allowing the tires to cool down and going back to 110 so that there is no tire failure.

We would suggest setting your TPMS max at about 120-125psi.

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Old 04-18-2017, 01:15 AM   #3
Brand: Thor Motor Coach
Model: Hurricane 35M
State: Virginia
Posts: 46
THOR #6664
Helps a lot--thanks Erich!
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Old 04-18-2017, 02:05 AM   #4
Senior Member
airforceret's Avatar
Brand: Thor Motor Coach
Model: Four Winds 26B
State: Indiana
Posts: 331
THOR #6414
When we crossed the great salt lake last year it was 100 degrees outside and the road temps were off the charts. In order to manage our tire pressures we had to keep slowing down until we were only running about 52 mph and the tire pressures stabilized. At one point I thought we might have to stop for awhile.
Roger, Dawn, and Roxie
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Old 04-18-2017, 02:39 AM   #5
Senior Member
Brand: Thor Motor Coach
Model: Hurricane 31S
State: Texas
Posts: 2,342
THOR #6411
If I remember correctly, dry air gains about 1 psi per 10 degrees temp increase. As the tires flex (tires are flat on the bottom) as you run down, the road generating heat. If the air in the tire has moisture, then the tire pressure increases much more as water vapor expands. I don't remember how much exactly. So the hotter, the tire the more pressure. Most tires are designed to run at 200 degrees F for their design life. So expect about 15 psi rise for a heavily loaded tire (somewhere near there designed max air pressure). A less heavily loaded tire will run cooler, but if you drop the pressure for a better ride, the tire will flex more and thus more heat and air pressure.
Jim & Roy Davis
2016 Hurricane 31S
1961 Rampside in tow
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