Nitrogen tire inflation can be an alternative to using regular air in your tires. As with most things, there are both benefits and downsides to this method.
Nitrogen Tire Inflation Benefits
There are more benefits than cons to using nitrogen tire inflation systems. The first advantage is that nitrogen is larger in structure chemically than oxygen. This will increase your tire pressure, and also keep more nitrogen in your tire since less can escape in the smaller holes. Having higher tire pressures for a longer time can help improve fuel economy, although this is only about a 3-5% gain. Nitrogen is much drier than the air that you put in your tires. Air can turn into water vapor at certain temperatures, which causes the tire to have a change in pressure. A nitrogen filled tire will not face this problem. Air will inevitably cause your tires to degrade due to the formation of rust. The oxygen will cause the iron and other metal to oxidize, which will form rust. Lastly, nitrogen is not combustible, so it is safer in the event of a fire, whereas oxygen will only add fuel it.
Nitrogen Tire Inflation Downside
There really only is one negative thing about using nitrogen in your tires, which is that it can cost a lot of money. Nitrogen is usually less available at select stations, and can cost you a bundle. It may cost more than $5 a tire to inflate. Not to mention, if you need to fill your tires up a bit, you may have to put regular air in since it may not be available where you are. This would lower the benefits of using the nitrogen.