Tire Pressure-Altitude v/s Temperature??

[Don Bradner]

I don't have a temp gun, but I've heard similar things from others. I can't
reconcile your small (10%) temp rise with the large (18%) pressure rise. That
doesn't agree with Gay-Lussac's law, which says that "The pressure of a fixed
amount of gas at fixed volume is directly proportional to its temperature in
kelvins."

That doesn't even count whatever expansion is allowed to occur by the elasticity
of the tire, which works to keep pressure down.

On 4/19/2007 at 8:26 PM dspithaler@... wrote:

>Don I'm running the Pressure Pros on mine this year to. On my way
>home
>from FL I started with 100 psi in the front in the morning & they went
>to 118
>psi. The tire temp was 124 degree with my temp gun. The out side temp was
>only about 70. I want to see what it does when it gets hot. I didn't
>notice it
>changing in the mountains of VA
>Don
>89 SP 36'
>Butler, PA
>
>run tire pressure monitors that can show me the pressure under way. Not
>uncommonly, tires inflated to 100psi at 70 degrees will show running
>pressures of
>120psi. if that is entirely due to temperature rise, the temps would have
>to
>go up 20%, is that true? That would be from 294 degrees K to 353 degrees
>K,
>or 176 degrees F. Is it possible that the interior of my tires get that
>hot,
>or is something else at work?
>
>The tires on my toad typically increase only 10%, from 33 to 36ps, which
>would correspond to running temps of 122 degrees F.

Don Bradner
90 PT40 "Blue Thunder"
Eureka, CA