Tire pressure before going south

The recomended pressure is for about 18degrC/65degr F to 20degrC/70degr F.

When ambiënt temp is lower the pressure is a bit lower too , wich gives more deflection so more heatproduction.
But then the cooling down is also more because of the moer temp difference between inside and outside tire. So you dont need to put higher presssure at lower temps.
The other way around when higher ambiënt temp , the cold pressure rises and so lesser deflection so lesser heatproduction, and because of lesser temp difference between in and outside tire the cooling down is also less .
to make it short , if you recalculate the pressure determined for 65 to 70 degrees for the ambiënt temp, the heatproduction and cooling down stays in line so no part of rubber of tire gets to hot.

For fuel saving its always better to keep the pressure higher also when cold, but then it will get to high when temp rises.

But an LT and Trucktire's maximum pressure on sidewall is not the maximum cold pressure but the presssure needed for the maximum load up to max speed of tire.
The maximum allowed cold pressure by the tiremakers system is 1.4 times this maxloadpressure/AT-pressure.
So if pressure rises above the AT-pressure given on sidewall cold, its not a problemm. Tires are tested to can stand a presssure of 2 to 3 times AT-pressure.

On Standard load and XL/reinforced/Extraload P-tires the maximum allowed cold pressure is given of between 44 and 51/ XL60 psi, and the AT-pressure is SL 35psi and XL// 41 psi in American system always.

This difference between AT and max pressure gives a lot of confusion , and AT-presssure is often called maxpress wich makes it more confusing.

Tire manufacturers compensate for temp changes. Always set pressure in the AM and don't change it until the next morning. They may fail for some reason but it won't be from failing to compensate for ambient temps.

Is the pressure stamped on the tire the cold pressure?

I use a tire monitor system for my fifth wheel and my truck has one from the factory. I have traveled a lot this last spring, summer and fall. I have gone from 40 degrees temps to 117 degree temps. Mountain range in the east and west. Did 14K miles and 26 states this summer. I keep my tires at or very near max cold pressure regardless of the outside temps. My fiver has 125PSI tires and my truck 65 and 80 PSI rear. I monitor the pressure with my gauges while driving which is pressure and temp on the trailer. Your pressure will rise and the tires will heat up. If they are at or near max in cold weather they will not diminish when driving and they will heat up as you drive. Maintain the recommended cold pressure regardless of the outside temp and you will be fine. Check you pressure manually at least once a week with a good quality gauge. It is not uncommon for tires on aluminum rims to lose a few pounds of pressure over a month or so.

Coach-man wrote:
People worry about tire pressure with temp's and altitude?

Yes we do and maybe you should to.

The pressure changes with temperature and altitude and if the swing is wide enough the difference in pressure can make a significant difference in tire wear and safety.

Those simple facts have not changed over the years.

I leave home (WI) in late Nov. after setting the air pressure for the temps there. When I get in warmer climate, I will eventually adjust the pressure for that part of the country I'm in. If I don't reset my TPMS system alarm with keep beeping.

Unless you inflate your tires to the max in minus degree weather, should not be a problem! People worry about tire pressure with temp's and altitude? May have been a problem years ago, but today's tires should be fine! Set at proper cold temp pressure and drive on!

X2

NHIrish wrote:

You need to check your tire pressures and adjust accordingly as you move from cold temps to hot temps...or the other way around,

It depends on where they are set to start with, in relation to the max. stamped on the sidewall.

Going from cold to hot, if the pressure at your morning check doesn't go above the recommended max. you can leave them alone until your destination.

Going from hot to cold, add about 4 LBS before you start out but not going over the max. That should get you well into your trip before you have to worry about adding more.

J&E wrote:
I am curious what others do about air pressure in your fifth-wheel tires. If you set it at proper PSI in the north at 30 degrees and then end up in FL at 90 degrees, what effect will that have on the tire pressure?

The answer to your question is that your tire pressure will be quite a bit higher in FL.

You need to check your tire pressures and adjust accordingly as you move from cold temps to hot temps...or the other way around, in both the trailer and tow vehicle. In your scenario, failure to do this will result in over inflated tires going north to south, or under inflated tires going south to north.