> PV = nRT ( T in Kelvin)
> It's all you need to know Angus. For tires, balloons, business meetings :)
> 

I knew I'd been missing something. It's all about hot air, says Alistair...

Angus

> 
> 
>> On Oct 19, 2015, at 3:53 PM, Angus Gordon <birdworks@GMAIL.COM> wrote:
>> 
>> 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