[DJJSR]

I tried using nitrogen in my drag slicks and here's what I found.........

The biggest reason tire pressures change when tires "warm up" is because the air contains moisture. Because the air comes from various sources, at various times, the amount of moisture in the air is unknown, so you don't know how much the pressure will change.

The use of nitrogen virtually eliminates the moisture, so you can determine pretty accurately how much the pressure will change as the temperature changes. This is not too important for a street car, but if you race on a road course or oval it can be very helpful.

My slicks were big. 34" diameter and 17" wide and used a LARGE volume of air (or nitrogen) but low pressure, only around 5 psi. At that low pressure, I found very little difference in the variation of pressure change using air vs. nitrogen. The pressure was closely monitored before each run and often changed in the staging lanes, so the use of nitrogen was not practical or economical for me. I did find that the tires leaked a little less, apparently because of the N2 molecules being larger.

As for the normal street car, my opinion is that it's a waste of money. If you hardly ever check your tire pressure, it may help because it may leak less. If you take care of your car like you should and check the pressure regularly, I think you will see zero difference in gas mileage or tire wear. But if it makes you feel better, do it. Placebos work! (ever notice how your car seems to run better after you wash it?)


FYI - Nitrogen is used in most types of pro auto racing to accurately determine pressure change. It's also used in commercial aircraft tires, but that's just to eliminate freezing at altitude.