Tire pressure at 144psi

[Husker]

The experts at etrailer say this: "When it comes to trailer tires you always want to have them inflated to their max psi when cold. Not only do you get the full capacity at the max psi, you also will generate less heat in the tire since there won't be as much flex in the sidewall, you'll get better wear and better fuel mileage."

[jbwilliams25]

I called Grand Design, Lippert and Cooper I was directed back to Grand Design. No one knew, or would give me any information.

[DECelt]

Thanks all. Today was another travel day and the pressures were the same. Sounds like it's normal. I'll call Cooper anyway next week to see what they say but all seems fine. We've got almost 6000 miles on her already, no issues!

Mine do the same thing ... But no problems yet. I was able to drop my cold pressure to 110-115 and have been more comfortable with the temps and psi.

[ajg617]

Here's the email response I received from Cooper April 2022 suggesting what alarm settings I should have on the TPMS. Personally I set my TPMS high pressure to 148PSI, low pressure to 122PSI, high temp to 150F.
"John:

The RV trailer should have a placard on it that states what the tires should be inflated to. The max / min pressure should be +/- 20% of that number. Cooper would recommend a max temperature of 180F. The inflation pressure should be set at the placard specified pressure. If there are large changes in ambient temperature, the inflation pressure should be reset to the target inflation pressure at the current morning ambient temperature.
This came from our Radial Medium Truck department for you.

David"

20% puts it at 150PSI max pressure.

[huntindog]

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.

Attachment 34997

I am in Arizona, I have the same tires I have seen temps in the 160s. Keep your tires at 125 cold.All tires are to be set that way, I states that on the sidewall.It is not the ambient temp as much as it is the temp of the asphalt. You can cook eggs on it in the summer. Don't over think it. Air is you tires coolant

[Hoopy Frood]

I am in Arizona, I have the same tires I have seen temps in the 160s. Keep your tires at 125 cold.All tires are to be set that way, I states that on the sidewall.It is not the ambient temp as much as it is the temp of the asphalt. You can cook eggs on it in the summer. Don't over think it. Air is you tires coolant

FWIW, I don't think it actually says on the tire sidewall to inflate to the max pressure. It just states the max carrying weight at the max pressure cold. At least that's what all the tires I've seen have on the sidewall. Tire threads always generate a lot of this-and-that.

[msutoad]

Living in NC, and traveling to FL during the winter months, I can have 40-50 degree ambient temp swings. When I know that is going to be the case, I do start my tires out below max PSI, so about 115 cold, and by the time I get to the freeway they are at 125, and by the time I travel to the first refueling stop, they are at 130-135 depending on outside temp. I rarely get above 137, but that is a 22 pound swing, which would freak me out to have mine at 147 if I started at 125. My temps stay between 100-115 on the tires, and only creap up higher if I am rollin strong (Speed increased).

Just sharing my "H" rated Cooper stats.
I try not to over think it. I have 20K + miles on my tires, and my routine works for me, and would only suggest those that are concerned to get a routine that works for them. Not everyone will have the same tires, rig, temps, speeds, destinations.

I appreciate the content we all put into this forum, helps keep me educated, so thank you.

[huntindog]

FWIW, I don't think it actually says on the tire sidewall to inflate to the max pressure. It just states the max carrying weight at the max pressure cold. At least that's what all the tires I've seen have on the sidewall. Tire threads always generate a lot of this-and-that.

The OP seemed to be questioning himself for setting the pressues cold. All automotive tires for steet use are set cold. One does not need to be concerned with psi rise as the tires warm up. Letting air out WILL increase sidewall flex which (undersame conditions) will increase heat build up. Trailer tires need to be set cold, and it is best to set them at max pressure. This makes the sidewalls stiffer to reduce sway, and they run cooler for better reliability. Which seems to be a major concern for most Rvers..... Based on the numerous tire failure posts....Why do anything to make them more failure prone?

[mwdilday]

I assume "ambient temperature" is outside air temperature. The Goodyear G114 H rated tires on my RV, with a cold air pressure of 123, will regularly exceed 140. Assuming you always check cold pressures before each trip and after any significant change in outside air temperature you should be ok with those pressures. Probably should check and adjust them before you head out after your next overnight stop.

[Hoopy Frood]

The OP seemed to be questioning himself for setting the pressues cold. All automotive tires for steet use are set cold. One does not need to be concerned with psi rise as the tires warm up. Letting air out WILL increase sidewall flex which (undersame conditions) will increase heat build up. Trailer tires need to be set cold, and it is best to set them at max pressure. This makes the sidewalls stiffer to reduce sway, and they run cooler for better reliability. Which seems to be a major concern for most Rvers..... Based on the numerous tire failure posts....Why do anything to make them more failure prone?

Not arguing with your advice, just pointing out that it says nothing about what pressure to inflate the tires to, just what the max pressure, and weight carrying capacity is. You said "All tires are to be set that way, I states that on the sidewall.", and I was just clarifying.