Thor Forums

[jadatis]

@CRIS1u( so no long quote again.

Differences between motor and RV.
Motor pressures in the range of 35 psi, and tires made for 99mph and more. then 4 psi rule OK.
RV often 80 psi or higher .
Then ,to get same temp in tire, the pressure rises more, about 10% is 8 psi for 80 psi.
And the 22.5 and 19.5 inch max speed 75mph .
Then temp in tire rises more at same speed and with that the pressure , so more then 10% pressure rising over 120 psi, so even 15 psi can be alright.

Then motors loading varies more, because driver and codriver and load, is bigger part of total weight.
RV, if you weigh them once per axle-end, the weights stay practically the same trough the years. So one pressure setting can do.

Then I read about motors with tmps, that calculate back the pressure to 65 degr F, so even totally warmed up with 140 degrF in tire, still gives the fi 35 psi , and not the 4 psi higher.

To get back to the original question, motortires mostly have a comfortable reserve in maximum load. RV often have tires to the limits.
So RV can have warm pressures higher then max allowed given on sidewall.