Find Your Credit Union

The Hype on Nitrogen -- It's a Lot of Hot Air

By KATE McLEOD, February 4th, 2012

Should nitrogen inflate your tires? "Deep Throttle," my secret source for automotive fact and rumor, tells me it isn't clear that nitrogen is necessary in passenger cars.

"It's good for performance-oriented cars," says DT, "Nitrogen doesn't expand as much at different temperatures. So when performance car tires get heated up, nitrogen helps to keep them uniform."

Investigating the use of nitrogen in passenger car tires with tire manufacturers and the Rubber Manufacturers Association, the conclusion seems to be consistent: there's a slight advantage, but if the tires are underinflated, then there is no advantage.

Forrest Patterson, technical director for passenger car and light truck tires for Michelin North America says, "The key to getting the most out of your tires is to maintain your tire pressure."

Compressed air, with which most passenger tires are inflated, is 78 percent nitrogen. The rest is oxygen, with about 1 percent other miscellaneous gases. Oxygen is corrosive and causes the gradual deterioration of tire rubber and tread and can cause rust on the metal associated with the tire. But, Michelin's Patterson says, "The benefit that you get from nitrogen is minimal if you maintain your tires."

Pressure and temperature exerted on a gas are what impact (tire) volume. The changes that occur with the tires are going to occur whether you use nitrogen or oxygen.

"In addition, all nitrogen suppliers are not equal. There are variations in the percentage of purity among vendors, so if you do decide to pay the cost of inflating with nitrogen, ask how pure it is," suggests Patterson. The better nitrogen claims to be 99.9 percent pure, while less than desirable nitrogen is 95 percent or lower.

Nitrogen costs money. Tire dealers, auto supply stores, some service shops and Costco will charge between $3 and $20 to fill with nitrogen. Some suppliers offer memberships for around $50 to allow refills for the life of the tire. Locations for suppliers of nitrogen for passenger tires can be found online.

We know that compressed air is usually free, although some fuel stations charge a few cents to fill. But it is critical to remember that if your tires are not inflated to the proper PSI, you are wasting your money. It is going out exhaust pipes because underinflated tires dramatically affect fuel economy.

There are arguments in favor of nitrogen. The main benefit seems to be that the nitrogen molecule is larger than an oxygen molecule, so it will take more time for nitrogen to escape between the threads of fabric that make up your tire. Tires will lose air or gas through the skin of the tire, but whatever is filling your tire can also escape through a faulty valve, an out-of-round wheel or by putting a tire over a curb at the wrong angle.

In high performance situations, nitrogen is noncombustible so with aircraft, mining commercial or heavy use it makes sense because nitrogen reduces the risk of fire if the brakes, rims or wheels overheat. In racing, nitrogen eliminates moisture and that helps reduce variations in tire inflation. According to the Rubber Manufacturers Association, in high performance applications, even a slight variation in moisture content impact high performance vehicles.

According to a survey commissioned by the Rubber Manufacturers Association, adult drivers check their tire pressure most often when gas prices are high at or near the $3.50 level. In 2011, 67 percent of those polled say they checked within a month, a six percent increase from 2009. Combining those who say they checked tire pressure over the last three months brings recent checkers to 83 percent. Men (73 percent) check more often than women (60 percent), but the percentage of women who check has increased eight percent from 2009.

So get in the habit of checking your tire pressure. And save the nitrogen for your next round of paintball.

Autonomous Driving: Our New Reality


Autonomous Driving: Our New Reality

Autonomous vehicles are on the road and being tested -- and predictions are that we're moving rapidly towards this reality. We contacted Ron Montoya, senior editor at and Jeremy Anwyl, an independent auto industry consultant and analyst by email to get their take on the issues.

The Used Porsche Test-Drive: So Far, So Good


The Used Porsche Test-Drive: So Far, So Good

You may recall, in part one of this story, we'd set out to learn whether one could truly find happiness behind the wheel of a $15,000 used Porsche. To recap, we'd just acquired the cleanest, most mechanically sound 2005 Porsche Boxster S we could find.

Meet Rich Miller: Nissan's Avid Outdoors Truck Man


Meet Rich Miller: Nissan's Avid Outdoors Truck Man

Rich Miller is chief product specialist of Nissan Product Planning for Titan and Armada and is a life-long truck enthusiast. Miller has been with Nissan trucks for over 18 years, and he has an inside view of what a customer wants and needs in the truck market segment.

Off Lease Vehicles

Hundreds of one owner, off-lease cars, trucks & SUVs with low mileage at a great price!

Additional Resources

Most Researched

2020 Honda Accord EX
EX 4dr Sedan
2020 Jeep Cherokee Limited
4x4 Limited 4dr SUV
2019 Audi A4 2.0T quattro Premium
AWD 2.0T quattro Premium 4dr Sedan
2020 Toyota RAV4 Limited
AWD Limited 4dr SUV
2020 Ford F-150 Lariat
4x4 Lariat 4dr SuperCab 8 ft. LB