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n4bme · 08-30-2021, 03:31 PM

The tires I have on my class C says 80 PSI max pressure which I need to keep them at for my weight but it does not say cold. The tires heat up about 10 degrees when travelling making them 90psi.

Should I fill them so they are 80 psi when running hot or assume they just didn't put the "cold" after max pressure. I can convince myself on either option so maybe I should get another opinion.

Mike

Winterbagoal · 08-30-2021, 03:35 PM

Cold is (probably) assumed.
80PSI maximum cold inflation pressure.
To be sure, contact the tire manufacturer.

wolfe10 · 08-30-2021, 03:40 PM

Cold is defined as: at ambient temperature before driving or exposure to sun or other heat sources.

And, BTW, that 80 pounds is not the maximum. It is the minimum PSI to carry the full rated load.

If your actual weight is lower, you can go to your tire manufacturer's Inflation Table to determine the correct MINIMUM PSI. Most add 5-10% to that minimum as a safety reserve.

And, absolutely, tire engineers knew exactly what PSI would do as their tires heat up. All is OK.

Winterbagoal · 08-30-2021, 03:50 PM

Quote:

Originally Posted by n4bme

The tires I have on my class C says 80 PSI max pressure which I need to keep them at for my weight but it does not say cold. The tires heat up about 10 degrees when travelling making them 90psi.

Should I fill them so they are 80 psi when running hot or assume they just didn't put the "cold" after max pressure. I can convince myself on either option so maybe I should get another opinion.

Mike

Here's a good article from one of the experts in tire inflation pressure recommendations. Personally, I run mine close to the max cold inflation pressure. Most tires are good up to well over 100PSI before you have to start thinking about popping one.
https://www.tirerack.com/tires/tiret...jsp?techid=196

sibe · 08-31-2021, 04:42 AM

reading here and there cold is normally 70-72, aka room temp.. as a start point..

Podivin · 08-31-2021, 04:48 AM

Quote:

Originally Posted by sibe

reading here and there cold is normally 70-72, aka room temp.. as a start point..

I believe 'cold' is the ambient temp, whether that's 20 degrees or 95 degrees, not a specific temperature. Otherwise it would be impossible to check and set the tire pressure on anything other than a 'perfect' day.

To the OP, it's expected for the pressure to rise when the vehicle is moving. Set/check your tire pressure before you start driving for the day and then don't worry about it.

jjrbus · 08-31-2021, 06:30 AM

Quote:

Originally Posted by n4bme

The tires I have on my class C says 80 PSI max pressure which I need to keep them at for my weight but it does not say cold. The tires heat up about 10 degrees when travelling making them 90psi.

Should I fill them so they are 80 psi when running hot or assume they just didn't put the "cold" after max pressure. I can convince myself on either option so maybe I should get another opinion.

Mike

Are you sure the psi is going up 10 psi with a 10 degree rise in temperature?

f14av8r · 09-01-2021, 04:55 AM

Quote:

Originally Posted by wolfe10

Cold is defined as: at ambient temperature before driving or exposure to sun or other heat sources.

And, BTW, that 80 pounds is not the maximum. It is the minimum PSI to carry the full rated load.

If your actual weight is lower, you can go to your tire manufacturer's Inflation Table to determine the correct MINIMUM PSI. Most add 5-10% to that minimum as a safety reserve.

And, absolutely, tire engineers knew exactly what PSI would do as their tires heat up. All is OK.

Perhaps you meant to say something different but if the tire says MAX INFLATION PRESSURE 80 PSI, that is indeed the maximum COLD inflation pressure, regardless of weight. And, as you said, the max inflation pressure also defines the maximum load the tire is designed to carry.