[TR] Inflating Tires w/ Nitrogen?

[Michael Marr]

>> I don't believe this is true.  Nitrogen is a gas and at the kinds of
>> pressures we are talking about it can be considered an ideal
>> gas, with
>> pressure, temperature and volume expressed according to the
>> relationship:
>>
>> pV = NRT
>
> I agree.
>
> However, there may be at least some truth to the claim that the pressure
> changes less with dry nitrogen than with wet air.  Water vapor doesn't 
> obey
> the ideal gas law very well, especially when it's saturated as can easily
> happen in a tire.  And since it's difficult to know how much water vapor 
> you
> got, it's also more difficult to predict how it will behave over
> temperature.
>
Good point - I agree totally.  A quick look at my steam tables shows that 
the specific vloume of water vapor changes at a much higher rate than dry 
air, for a similar temperature and pressure change.

Mike