Tire pressure increase at summer temperatures
I am fairly new to class A traveling so I'm seeing things for the first time. Before I begin a trip my tires register between 101 and 104 psi on my TPMS. They are 16 ply and can handle up to 120 ps...
Forum Discussion
The, what you think is, maximum pressure of tire, is not, maximum pressure cold is about 1.4 times that 120 psi = 168 psi.
I once read that they test tires to can stand an absolute ( over) pressure of 2 to 3 times the AT-pressure of yours 120 psi .
so even when warm they will blow somewhere between 240 and 360 psi.
So dont be affraid if pressure goes over 120 psi warm.
If you would fill cold at 32 degr F/0 degr C that 1.4 times 120 psi so 168 psi , and if temp in tire rises to 212degr F/ 100 degr C, the pressure would rise to 235 psi when dry air.
Can come to that at max 14,5psi by water in tire = 250 degr F.
This all ofcource will never happen for most in practice.
This must also count for the rimms, the maximum pressure they give is cold pressure, and higher pressure when warming up they can stand.
For truck tires , wich in fact your tires are, tire makers alow 20 psi over the At-pressure cold pressure.
For valves I once asked a valve importer in Holland( Europe) and there are testing standards , and what they give as maximum is cold pressure at 18 degr C/65 degr F , and rising pressure by rising temperature is standard included that they must stand.
Normal rubber snap-in valve - cold pressure maximumm 4.5/4,8bar/65/70psi( depending on brand) and mildest american standard 1,8 bar/26 psi higher when warm. DIN and ETRTO standards more extra pressure teststandard.
Metal valves can stand at least a cold pressure of 10 bar/145psi and also there pressure rising by temp rising they can stand.
I once read that they test tires to can stand an absolute ( over) pressure of 2 to 3 times the AT-pressure of yours 120 psi .
so even when warm they will blow somewhere between 240 and 360 psi.
So dont be affraid if pressure goes over 120 psi warm.
If you would fill cold at 32 degr F/0 degr C that 1.4 times 120 psi so 168 psi , and if temp in tire rises to 212degr F/ 100 degr C, the pressure would rise to 235 psi when dry air.
Can come to that at max 14,5psi by water in tire = 250 degr F.
This all ofcource will never happen for most in practice.
This must also count for the rimms, the maximum pressure they give is cold pressure, and higher pressure when warming up they can stand.
For truck tires , wich in fact your tires are, tire makers alow 20 psi over the At-pressure cold pressure.
For valves I once asked a valve importer in Holland( Europe) and there are testing standards , and what they give as maximum is cold pressure at 18 degr C/65 degr F , and rising pressure by rising temperature is standard included that they must stand.
Normal rubber snap-in valve - cold pressure maximumm 4.5/4,8bar/65/70psi( depending on brand) and mildest american standard 1,8 bar/26 psi higher when warm. DIN and ETRTO standards more extra pressure teststandard.
Metal valves can stand at least a cold pressure of 10 bar/145psi and also there pressure rising by temp rising they can stand.
