nitrogen in tires

["Michael Wendell" <mwendell@xxxxxxxxxxx>]

in response to mr law's suggestion that you put nitrogen in your tires
before attending a driver's school, robert rose said:

> This sounds totally bogus. Snake oil.
>
> First off... Do you know what "regular air" is?
> Well it's 78% Nitrogen, 21% Oxygen, 0.03% Carbon
> Dioxide, and misc. gases. So any alleged benefit
> must be due to the removal of the Oxygen or Carbon
> Dioxide and not due to the Nitrogen.


i don't know if i agree with some of the claims mr. law has made about
nitrogen, and i honestly think that putting it in your tires for a BMW
CCA driver's school is OVERKILL.

however...

the fact is that every professional racer, and more than a few amateurs
use nitrogen in their tires. the reason is simple. nitrogen from a tank
is extremely dry. it doesn't contain the moisture found in ambient air.
becuase of this, when heated it expands by only a small fraction,
compared to regular air, which is quite moist, and expands much more
dramatically.

this allows the racer to have much greater control over cool vs. hot
tire pressures.

they're certainly not using it for any marginal tire-life issue which
might come from oxygen molecules working their way into the tread of the
tire as the research pointed out by mr. law might suggest.

personally, i raced SCCA for a while (anybody want to buy an ITB 318i?)
and always used regular air to fill my tires. nitrogen just wasn't in
the budget. instead i just learned that my tire pressures would increase
by a certain amount at each corner, and adjusted the cool pressures
accordingly.

m.

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