Appropriate Tire Pressure?
I have a 25' Class B+ motorhome. It has 16", Load E tires rated at 80psi cold. Is it safe to run them anywhere between 65psi - 80psi cold? I currently have them inflated at 70 psi, we have an average...
Forum Discussion
The whole subject of tire pressure is one I find amusing, the part about ‘4 corner weighing’ hilarious!
Tire pressures are of course best taken when the tires are cold. However, as a tire starts to roll that little flat spot at the bottom, and the 2 little bulges in each sidewall, move along the circumference of the tire to stay in contact with the road. This flexing and relaxing cause heat. An average size tire turns about 750 times to cover a mile, so at 60mph those tires turn 750 rpm. After just a half an hour the tire temperature can rise 50 deg’s. Tire pressure increases by about 1 degree per 10 deg increase in tire temperature.
From the time you check tire pressure at say 9am and find then at say 60 deg’s, to a sunny hot afternoon of 90 deg’s and 6 hours of highway driving the tire pressure could have easily changed by 10 psi.
Oh, but on a snowbird dash south on a cold rainy early winter day, they may have only increased by 3 or 4 degrees.
So much for precise pressure settings ………
Tire pressures are of course best taken when the tires are cold. However, as a tire starts to roll that little flat spot at the bottom, and the 2 little bulges in each sidewall, move along the circumference of the tire to stay in contact with the road. This flexing and relaxing cause heat. An average size tire turns about 750 times to cover a mile, so at 60mph those tires turn 750 rpm. After just a half an hour the tire temperature can rise 50 deg’s. Tire pressure increases by about 1 degree per 10 deg increase in tire temperature.
From the time you check tire pressure at say 9am and find then at say 60 deg’s, to a sunny hot afternoon of 90 deg’s and 6 hours of highway driving the tire pressure could have easily changed by 10 psi.
Oh, but on a snowbird dash south on a cold rainy early winter day, they may have only increased by 3 or 4 degrees.
So much for precise pressure settings ………
