--- Paul Root <ptrmgb@gmail.com> wrote:
> And they use Nitrogen to fill tires, and charge for
> that.
> Which brings up one more question, why Nitrogen?
Two answers here. First answer: Simple compressed air
contains quite a bit of water vapor, steam if you
will. Water has a MUCH higher expansion with regard
to temperature than does nitrogen. The upstart of
this is that a tire filled with nitrogen with increase
in pressure very predictable with increase in
temperature. A tire filled with moist air will also
increase in pressure but the change will be
unpredictable because the actual humidity of the air
is unknown, and therefore the amount of water is
unknown. Second answer: Some claim that the effect
described in part one is minimal and the importance of
the issue is just urban legend. Then again, ALL race
teams use nitrogen. I use plain old air in all my
cars - except the Ferrari. For it, I have a paint gun
air drier in the compressor air line. Then again,
everything about the Ferrari is about doing just a
little extra. That's the fun bit. :-)
regards,
rick
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