Tire pressure at 144psi

[steve95628]

Wondering if this is ok for Cooper RM170 tires to get to 144psi. I fill them cold to the stated pressure on the placard of 125psi. The spec sheet for these tires states max pressure of 125psi. I assume that's cold tho.

Traveling through the southwest with ambient temps over 100.

[Tgunter5]

Seems like a rather large increase for such a low temperature. I recently installed a factory TMPS and cold pressure is 65 PSI, while traveling they increased to 71 PSI and the temp was up to 135 degrees F. Sorry I can't give any more guidance.

[fez111]

Seems like a rather large increase for such a low temperature. I recently installed a factory TMPS and cold pressure is 65 PSI, while traveling they increased to 71 PSI and the temp was up to 135 degrees F. Sorry I can't give any more guidance.

Having had two blowouts on our previous 5er and then another with a $1750 insurance claim on our Solitude, please let me add my 3-cents worth...

Our 2010 Rockwood UL 5er came with load range "C" tires. It blew one that I had set to max cold pressure. Next trip we blew one that was set 20 PSI under max cold pressure. Our Solitude came with Westlake load range "E" tires. On the 70 degree morning that our third blowout happened I had carefully set all four tires to the max cold pressure of 80 Psi, as many on this forum have stated to be the correct way set tire pressure. 90 minutes later I was on the side of the freeway changing a blown tire amidst the shrapnel of my wheel well! The other three tires were at 100 PSI! I let some air out for the rest of the drive home.

That day I made two decisions! One was to buy only Carlisle tires. I had Carlisle tires on my 39 ft. 1987 Layton for 20 years with no problems. Four more Carlisle's were on that trailer when I sold it 5 years later. After the Westlake blowout I purchased new 16 inch Carlisle trailer radial tires that are 15-Ply load range "G" and rated 110 PSI cold. My alloy wheels are rated 110 PSI.

Two, I bought an EEZ-Tire monitor system. Mine has 10 sensors with a repeater (42 ft. trailer). I could not believe what I found... My tires GAIN 25 - 35 PSI each while traveling at 62 MPH. It happens faster when its hotter out, and the tires on the sun-side gain 10 LBS more than the shade-side. I asked my tire guy what pressure to start, and we decided on 95 PSI. That lasted an hour until I was in a rest area letting air out of my tires. Maybe the tires can take more pressure than the cold max of 110 but my rims cannot.

Over the last three years I have mostly perfected my system... I make sure the trailer tires (Carlisle's) are between 85 and 90 PSI. when we start out. If it is not very hot outside then my tires will stop gaining pressure just under 110 PSI. If it is sunny and 85+ degrees then the pressures rise faster and flirt with the 110 max cold PSI. I may have to eventually let some air out.

Disclaimer: There are folks on this forum that will vehemently disagree with my logic and procedures. I do not know what they have tried or how many blowouts they have had. I KNOW how many we have had and what has worked and what has not. I also know that no Carlisle tire has never let me down and since I got the EEZ-Tire monitoring system (knock on wood) I have never had a blowout in three trips from Michigan to Florida and back and a myriad of 2-3 hour vacation trips.

There's my 3-cents...

[OurNewEra]

Wondering if this is ok for Cooper RM170 tires to get to 144psi. I fill them cold to the stated pressure on the placard of 125psi. The spec sheet for these tires states max pressure of 125psi. I assume that's cold tho.

Traveling through the southwest with ambient temps over 100.

I have tires with max cold pressure of 80 PSI. I see them go up to about 89-91 psi with internal tire temps in the low 100's. This with ambient at about 90 deg. Of course this will vary as ambient temperature varies.

Here is a web link to an article by Roger Marble.

https://www.rvtravel.com/rver-concer...sure-increase/

His Tire Safety site states that ". . . tire pressure will change about 2% for every 10 deg F change in temperature." So basic math says that the higher your cold PSI then your 2% will be a higher number than what I get on a lower cold PSI tire.

The 'Tire Safety' site has been posted in many other threads on tires and provides very good information. IMHO.

Of course this all depends on road conditions, trailer weight, and speed. If your trailer is overloaded it would cause an increase in internal tire temperature which would drive up your hot PSI. I do agree with @Tgunter5 that your internal temperature does seem low for the increase in tire pressure.

[jkwilson]

Wondering if this is ok for Cooper RM170 tires to get to 144psi. I fill them cold to the stated pressure on the placard of 125psi. The spec sheet for these tires states max pressure of 125psi. I assume that's cold tho.

Traveling through the southwest with ambient temps over 100.

What was the air temperature when you last adjusted pressure?

[steve95628]

About 70 degrees. The increases make sense, just wondering if that high a pressure is safe.

[OurNewEra]

About 70 degrees. The increases make sense, just wondering if that high a pressure is safe.

Out of curiosity I did the math using the 2% of PSI for every 10 deg F. Using 125 psi at 70 degrees as the starting point, the tire pressure at 120 degrees calculates to 138 psi

[BobLandry]

I'm also running Cooper LTs with a max cold pressure of 80psi. I assume the manufacturers allow for expansion

[Cannon07]

My G rated start out at 110psi. Most of the time they hit 127, 128. I have seen the hit 130 to 132 on a day when it's in the 90's.

[LanerC]

My G rated start out at 110psi. Most of the time they hit 127, 128. I have seen the hit 130 to 132 on a day when it's in the 90's.

same as mine do.