Tire Pressure-Altitude v/s Temperature??

[Pete Masterson]

The heat generated by the rolling resistance of the tire is the
reason the pressure reading increases. Tires are manufactured with
this in mind -- you should not reduce the pressure of a 'hot' tire as
it will be under inflated and will generate even more heat in operation.

The large tires on a truck or Blue Bird generate considerable heat
when in operation. Perhaps someone who has one of those infrared
thermometers would care to comment.

As for the earlier comments ... I suspect that there was a concern
that the tire pressure should be reduced at altitude -- but the
difference is rarely significant enough to worry about. Remember,
rubber tires are used on airplanes, mostly stored in unpressurized
compartments -- and they don't "blow out" due to changes in altitude
ranging from near sea level to 30,000 to 40,000 feet.

Pete Masterson
'95 Blue Bird Wanderlodge WBDA 42
aeonix1@...
On the road at Johnson City, Texas -- home of LBJ!



On Apr 19, 2007, at 5:55 PM, Don Bradner wrote:

> OK, all makes sense, but I wonder about this:
>
> I 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.
>