Originally Posted by
DrIsotope
Tire places hawk nitrogen to drivers because it leaks out of the tire much more slowly than atmospheric air. It's also dry, which is a good thing for tires. Nitrogen-filled tires can go 6+ months with no loss of pressure.
Race cars use nitrogen because it doesn't react nearly as much to changes in temperature. I did tire and suspension setup as part of a short-track pit crew for several years. Tires filled with air could swell by +10psi as the tire heated from ambient to +180º. The same tire filled with nitrogen would only change 1-2psi. Higher pressure changes the rollout of the tire, which changes the stagger of the tires (for circletrack racing, the tires on the left are smaller than the tires on the right) which alters the handling of the car.
I'd love to be able to fill my tires with nitrogen. Dry, leaks out more slowly. No real drawbacks.
Moisture in the air causes a major portion of the pressure changes. Back when I was working on a CanAm team we tested using compressed air (which was pretty much the standard at the time), dry compressed air, and nitrogen. Nitrogen was the most stable, but dry air was only about 1psi worse over the tire temp range than the nitrogen fill. After some discussion we decided that it would be easier to carry a couple of extra nitrogen bottles (we used them in the pits anyways) and use it to fill the tires rather than adding an air dryer to the compressed air system in the transporter.
G sized nitrogen bottles aren't that expensive from the local welding supply shop. Once you have the regulator it isn't too expensive to keep a bottle around. And if you close the bottle after use it easily lasts a couple of years.