Nitrogen in tyres is becoming a popular replacement for standard compressed air. Nitrogen has many advantages over oxygen / compressed air. With nitrogen tyre inflation, improvements can be seen in vehicle handling, fuel efficiency and tyre life through better tyre pressure retention, improved fuel economy and cooler running tyre temperatures.
Nitrogen's larger molecular size decreases the rate at which it escapes through the rubber of the tyre, keeping the tyre properly inflated over a longer time. However, it's not all about the nitrogen, it's about reducing oxygen and moisture. Oxidation can damage the tyre and it's components, as well as the wheel. During use, a tyre heats up and the rate of oxidation increases. Compressed air also contains moisture which can increase oxidation and cause pressure fluctuations. While nitrogen will help you maintain proper pressure, you should still check your tyres on a regular basis and/or as recommended by the tyre manufacturer.