Tire pressure before going south
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 ...
Forum Discussion
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.
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.
