Dear Tracy,

Are there real advantages to inflating my tires with nitrogen instead of air? Is nitrogen that much different than air?

-Karl M.

Dear Karl,

Nitrogen is becoming more widely available as an alternative to air for inflating tires. While the air ordinarily used to fill tires is already 78% nitrogen, advocates say that filling with pure (93% to 95%) nitrogen does make a difference.

Nitrogen is said to be less sensitive to outside temperatures and better at maintaining tire pressure. Since nitrogen is supposed to maintain tire pressure better under hot and cold conditions, it can improve gas mileage, increase tire life, and is safer because tires are less likely to blow-out when driven at high speeds. Due to the fact that nitrogen is dry and does not support combustion, it has long been used in applications such as aircraft tires and racing tires, in which tires run extremely hot.

Another advantage said to be gained with nitrogen is that, as a dry gas, it reduces oxygen and moisture. This is important because oxidation accelerates as the tires heat up, causing damage to the tire and wheel. Air contains moisture, which increases oxidation and pressure fluctuation.

Some of the research available seems to suggest that while there are advantages to nitrogen use, the actual benefits tend to be modest.  Since you typically have to pay for nitrogen inflation, some drivers may not feel the benefits are worth the expense.

It is important to note that a big factor involved with the benefit of nitrogen is tire pressure. Checking and maintaining proper tire pressure will provide you with a host of benefits including longer tire life, improved safety, and better gas mileage, whether you fill with nitrogen or regular air.