Nitrogen or Air: Is There a Difference?

Dear Tracy,
I am considering inflating my tires with nitrogen instead of air. Can you tell me if there are benefits to using  nitrogen, or is it not that much different than air?
-Cory H.

Dear Cory,
According to the nitrogen proponents, benefits to choosing nitrogen over air include increased fuel economy, longer tire life, and improved handling.  Though the air ordinarily used to fill tires is 78% nitrogen, supposedly filling with pure (93% to 95%) nitrogen does make a difference.

Nitrogen is reported be less affected by outside temperatures and more reliable for maintaining tire pressure. Because nitrogen is supposed to do a better job of keeping pressure under hot and cold conditions, it can improve gas mileage, increase tire life, and is safer because tires are not as likely to blow-out at high speeds. Since nitrogen is dry and does not support combustion, it has long been used for aircraft and racing cars, which require tires to run extremely hot.

Another advantage advocates tout with nitrogen is that it is a dry gas, and as such reduces oxygen and moisture. The reason this is significant is because oxidation accelerates as the tires heat up, leading to  damage to the tire and wheel. The moisture in air increases oxidation and pressure fluctuation.

So, the question is, are these claims true? Some research suggests that while there may be advantages to nitrogen use, the tangible benefits tend to be modest.  Since you usually have to pay for nitrogen inflation, some feel the benefits are not worth the expense.

It is important to note that whether you choose air or nitrogen, the key is tire pressure. Checking and maintaining proper tire pressure will assure you of longer tire life, improved safety, and better gas mileage, whether you fill with nitrogen or regular air.