Re: nitrogen in tires

["Armand Eshleman" <aje1@xxxxxxxxxxxxxxx>]

The real reason racers use nitrogen in the tires is because of consistency.
When an air compressor compresses the air it also carries with it the
moisture
in the air. When "wet" air is used in a racing tire it creates trouble. A
tire at
ambient temperature with wet air in it will increase the pressure more
dramatically
because water vapor turns to steam and expands at a much greater rate at and
above
212 Fahrenheit. A road/oval racing tire can reach temperatures of over 230 F
during
a heat cycle, more than enough to create excessive expansion of the water
vapor.
 Steam does not have to be made inside the tire to hurt its performance,
very hot air with water vapor in it will grow in volume compared to when it
was "cold"
and increase the pressure which changes the tread contact with the
track surface. Nitrogen on the other hand has no moisture in it, just pure
nitrogen.
It is very stable and the volume increases very little when heated,
especially compared to
water vapor. The SCCA Formula Ford racing teams I was around used nitrogen
way back
in the 1980s for the advantage of consistent tire pressures and temperature
which relates
directly to tire performance and lower lap times.
On the other hand for street use the advantage would only be to prevent
corrosion, and I
can't see the benefit of worrying about that unless you are using unfinished
steel wheels. A
set of tires will not last long enough to dry rot because of moisture. Worry
more about
sun exposure. I have a set of tires still on my Javelin that I purchased in
1976. They are
mounted on slotted chrome steel wheels. I would venture to bet that there is
very little to no
corrosion inside the wheel and tire space. The tire has weather checked from
the outside in, not
the inside out. Aluminum wheels may not fare as well, moisture may cause the
aluminum to
oxidize on the inside over a period of many years. How many of us keep a set
of wheels long
enough for real damage to occur. If you do then go for the nitrogen.
As Bruce might say, " Hey that just my experience yours may differ."

Armand