+1 to what [MENTION=54249]RayVoy[/MENTION] said. People just need to get educated on Nitrogen. It's a bit of scam for us everyday-motorists. Dealerships charge you tons of money for very little, if any, benefits. Also, racecars use pure nitrogen in the tires because pure nitrogen (or any gas really, as long it is pure) has no water vapor in it. The air we breathe has lots of moisture in it and pure nitrogen eliminates the moisture content. By eliminating the moisture content, the pure nitrogen in the tires has a much more predictable pressure behavior. As heat builds up in the tires and increases the pressure of the gas inside, race teams can better predict how much pressure they can build up. Varying tire pressures, even just half a PSI, effects how the tires handles a turn.