[BlackinBlack]

I always find this debate funny. There is one reason that race teams use nitrogen. Consistency. Air is not a consistent mix of gases. What that means is that air expands and contracts at different rates when heated and cooled.

In a race car they measure PSI in 1/4 increments and small changes in pressure can mean the difference between a well handling race car and one in the wall. Knowing how much the pressure increases when heating the gas in the tire 10 degrees is a must. (And the rate of expansion of pure nitrogen is very easy to figure out. It is cheap, common and inert so that is why they use it.)

So.... unless you are measuring the gas in your tire to the 1/4 pound while you are driving on the very edge of the cars capability and that last .01 of a second means the difference between a million dollar payday and losing a race. Nitrogen is not needed.... but if it makes you feel better put it in and spend the extra $$.

Me I will stick with free air just like GM spec'd for the car.