Can You Mix Air and Nitrogen in Tires?

Air is composed of 78 percent nitrogen, 21 percent oxygen and one percent other gases. This means that, even when regular compressed air is used, the gas inside a tire is mostly nitrogen. According to the Get Nitrogen Institute, filling tires with almost pure nitrogen improves fuel economy, increases tire life and leads to better handling. However, a report by Edmunds Inc. suggests the benefits of nitrogen in tires may be overstated.