Thanks David, I've been using a rule of thumb of 1% per 5F for a long time but I don't know where it came from. Michelin perhaps. Normally I only use it to overinflate when headed to a cold destination. Kept me out of the weeds so far...

Angus

> On Oct 19, 2015, at 3:46 PM, David Beierl <dbeierl@attglobal.net> wrote:
> 
> At 11:19 PM 10/17/2015, Angus Gordon wrote:
>> I have experience with nitrogen filled tires on aircraft and can tell you that it certainly doesn't negate pressure changes with temperature. That's still something we deal with. I don't see any real value in using nitrogen in car tires.
> 
> I believe pressure change as a percentage per degree will be essentially the same no matter what gas or combination of gases is used to fill a tire.  It amounts to roughly one psi per ten degrees Fahrenheit for tires at ordinary pressures and temperatures.
> 
> Yrs,
> d