Text size: Normal Text Size Large Text Size
July 20, 2009

The benefits of nitrogen inflation

A lot of claims have been made about this polarizing topic. MTD revisits its past stories to see if they need claims adjustments

In MTD’s November 1967 issue, the pros and cons of nitrogen inflation were discussed when Gulf Oil began test marketing the service in Houston, Texas.

In MTD’s November 1967 issue, the pros and cons of nitrogen inflation were discussed when Gulf Oil

No service elicits more positive and negative feedback from our readers than filling tires with nitrogen. Modern Tire Dealer has written on the subject for decades, yet nitrogen still has its detractors.

Back in 1967, our November cover featured Gulf Oil Co.’s attempt to test market nitrogen inflation at 41 of its stores in Houston, Texas. Its supplier, Big Three Industrial Gas & Equipment Co., charged $6.75 for a 300-cubic-foot bottle of nitrogen. Gulf Oil charged its customers $1 per tire.
(Jerry White, chairman emeritus of White Tire Supply Inc. in Beaumont, Texas, says he pays $23 for a 230-cubic-foot cylinder of nitrogen.)

And how can we forget the “nitrogen tire car” that was displayed at the NTDRA trade show in 1996? The car was driven 33,000 miles through 15 countries from Brazil to the United States (though when one of the tires had a blowout, it was replaced with one filled with air).

Not until July 2004, however, did we start to look at the possibility of nitrogen fill becoming a mainstream automotive service.

Since then, we’ve written at least one story a year on the topic. We have approached it from every conceivable angle, from why it works to how it is marketed.

Nitrogen people, tire dealers and, yes, even we have made many claims in those stories. Our most recent anti-nitrogen e-mailer simply said we have failed to present both sides of this issue.

Today, nearly one third of independent tire dealers offer nitrogen. In our “2008 Nitrogen Inflation Service Survey,” 89.2% reported they charge at least $1 per passenger tire for the service; 80% charge $5 or more per tire. For light truck tires, 94% of the dealers charge at least $1 per tire, and 80.1% charge at least $5.

Tire Discounters Inc., the 14th largest independent tire dealer in the United States, only offers nitrogen as a tire fill.

So, are the claims we have written about valid, or are we in for claims adjustments? Are we following our Mission Statement, which requires us to help you run your businesses more profitably? Here’s a time line of a representative sample of MTD’s stories, what was said, and if the claims were justified.

July 2004: “Nitrogen: no, niche or now?” The use of nitrogen instead of compressed air was being considered by some “pretty heavy hitters” at the time, including Dunn Tire LLC, Conrad’s Total Car Care & Tire Centers and the Zurcher Group. Tire Discounters and Costco Wholesale already were on board.

“Time will tell if it’s a fad, but there are a lot of pluses in nitrogen’s favor — and few minuses,” we wrote.

CLAIM: Tires hold their psi longer with nitrogen than air. This is true, although we said that was because nitrogen has more mass than air. As Dr. Ray Bergstra, armed with his Ph.D. in chemistry, informed us after the fact, nitrogen has slightly less mass than air. It diffuses through tire walls more slowly because it has larger molecules.

A University of Bologna study concluded that tires inflated with nitrogen lose pressure at a slower rate than a tire inflated with air, 1.6% over the course of a month versus 3%. According to the results of a 12-month test of H- and V-rated all-season tires conducted by Consumer Reports, tires filled with 95% nitrogen lose psi at a slower rate than tires filled with air. Over a 12-month period, the average loss in the nitrogen-filled tires was 2.2 psi, compared to 3.5 psi for the air-filled tires.

(In the Consumer Reports test, the tires were placed outdoors; an engineer told us that everything being equal, the rate of loss in stand-alone tire and wheel packages versus tires in use would be about the same.)

CLAIM: Nitrogen runs cooler than air. False. The temperature of nitrogen gas doesn’t fluctuate, which helps the pressure stay more consistent. As a result, the tire runs cooler because it remains properly inflated. This is one of the reasons that aircraft and racing tires use nitrogen.

CLAIM: Nitrogen drastically reduces oxidation on the rim and inner-liner because oxygen is almost totally eliminated from the mix. This is true. Air is made up of about 78% nitrogen, 21% oxygen and 1% argon and other inert gases. The more oxygen you replace with nitrogen, the less oxidation.

Less oxidation and moisture helps the tire last longer.

CLAIM: Tire life can be increased by up to 26%. The number is just a little high, based on the Bologna study. “If the oxygen concentration inside the tire is reduced by 6%, the life of the... car tires (is) increased by 22%.” The use of 99.9% nitrogen increased average tire life by 25%.

In a nutshell, nitrogen keeps the tire properly inflated longer than air, which leads to less rolling resistance, which leads to greater fuel economy and extends tire life.

August 2005: “More than a passing fad.” Although radio personalities Click and Clack talked about the advantages of nitrogen, they ultimately concluded that “none of these advantages are important to the average driver.” Dunn Tire Chairman Randy Clark was among four dealers who disagreed with that theory.

“If you maintain air pressure all the time, the benefits of nitrogen diminish,” said Clark. “But the average customer doesn’t do that.”

Of the more than 5,500 vehicle tire pressures checked by the Rubber Manufacturers Association (RMA) as part of its “2009 Tire Pressure Survey,” 91% had at least one improperly inflated tire, and 19% had at least one tire under-inflated by 8 psi.

The use of nitrogen is not a replacement for regularly checking tire pressure, and all nitrogen suppliers readily admit that. However, it is not realistic to believe that the majority of car owners will change their driving habits anytime soon, given RMA research.
CLAIM: Filling a tire with nitrogen “is no more difficult than filling a tire with air,” said one dealer. It may not be more difficult, but it definitely takes more time because of the purging.

If a nitrogen generator fills a tire with, say, 95% nitrogen, that doesn’t mean it has 95% nitrogen in it when the desired psi is reached. Even when flat, the tire contains air. For a 95% concentration of nitrogen, it typically takes two purges at a higher concentration.

What purity level will give you the benefits of nitrogen? Industry participants are still debating that issue.

The Get Nitrogen Institute (www.getnitrogen.org) says 93% nitrogen in the serviced tire is enough to gain the benefits of nitrogen inflation. Others put the minimum at 95%. One engineer with whom we talked said it has to be 99% pure or the benefits will be minimal at best.

A study by Ford Motor Co. found that the use of a high purity level of nitrogen in tires can “significantly” slow down or even halt tire aging compared to air-filled tires. In “Effects of Nitrogen Inflation on Tire Aging and Performance,” authors John Baldwin, David Bauer and Kevin Ellwood tested tires filled with air, 96% nitrogen and 99.9% nitrogen. They wrote that the performance results at 96% were not substantially different than at 99.9%.

“This is important for the average consumer because the need to purge existing tires completely of air before filling with nitrogen may not be necessary,” they concluded.

We also addressed myths and misconceptions about nitrogen that we had come across.

CLAIM: Nitrogen inflation equipment produces 100% nitrogen. False. We wrote that to get an efficient source of close to 100% nitrogen without using bottled nitrogen, filtration systems would have to be quite large. Plus, the compressor needed to pull the nitrogen out of the air would have to run longer, which would lengthen the time to provide the service. The realistic industry target for nitrogen inflation generators is anywhere from 95% to 98%. And again, the tire has to be purged of as much air as possible to get that level of purity in the tire.

July 2007: Nitrogen pioneer. Olin Mott, owner of Olin Mott Tire Co in Tampa, Fla., was promoting nitrogen use in his ads in 1963. He didn’t charge for it then, and builds the cost into the tire now. His 1963 article had three claims.

CLAIM: “Nitrogen is a known coolant.” Well, liquid nitrogen is. And nitrogen condenses into a liquid at minus 320.4 degrees Fahrenheit (minus 195.8 degrees C). As we mentioned earlier, it helps the tire run cooler by keeping it properly inflated longer than air.

CLAIM: “Properties of nitrogen minimize deterioration of rubber and tire cords.” If the purity of nitrogen in the tire is high enough, yes. In the Ford study, the authors concluded that “the oxidation of the steel-belt rubber is truly driven from the contained air pressure inside a normal passenger or light truck tire.”

CLAIM: “Nitrogen is used in airplane and racing tires.” This is still true of both, which feature high psi requirements.

May 2008: “Inflation proclamation.” The story addressed how to let your customers know you offer nitrogen, and how to convince them to pay for it. It “is not going to sell itself,’ said Terry McCune, Big O Tires Inc. in Livermore, Calif. The key was being relentless in informing his customers that he offered the service.

CLAIM: “For customers who drive a lot, nitrogen makes a big difference in their pocketbooks,” said McCune, who uses ready-made tools like fuel savings calculators on various Web sites, including www.getnitrogen.org). We checked out three such calculators, one from a supplier, one from a dealer and one from www.getnitrogen.org. We put in these numbers:

Miles driven per year: 15,000

Average cost of gas/gallon: $3.60

Average miles per gallon: 20

The savings in annual fuel costs because of the improved mileage was 3.3%, 3.6% and 5.5%, respectively. That, of course, is assuming that the air pressure is not checked regularly.

The average fuel savings by using nitrogen, all things being equal, is about 3.3%, according to the Get Nitrogen Institute, www.fueleconomy.gov and a Canadian study of trucking fleets conducted by a nitrogen tire inflation equipment supplier.

The U.S. Department of Energy and U.S. Environmental Protection Agency estimates that for every 1 psi drop in tire pressure, there is a 0.3% drop in gas mileage.

In summary, the benefits of nitrogen over air in a tire are valid, based on our research.

The degree of benefit to the consumer depends on the percentage of nitrogen in the tire (remember, the existing air in the tire will dilute any concentration of nitrogen pumped into it), but there are a lot of measurable benefits.

A tire that remains properly inflated longer deflects less than an under-inflated tire, which helps it run cooler, wear evenly and roll more freely. The result is increased tire life and improved fuel economy.

In addition, less oxygen leads to less oxidation and moisture. That, in turn, helps reduce wheel corrosion and tire structural integrity degradation.    ■

Related Topics: Nitrogen, nitrogen tire filling

Share this:  Share on Facebook Share on Twitter

Request more info about this product / service / company


  1. tony | July 29, 2009 at 11:13AM
    We have also installed nitrogen in motorcycle tires. Above the added benefit of pressure retention, nitrogen also improves the ride quality.

  2. michael | September 03, 2009 at 01:13PM
    The oxidization of the tire is more a fact of good old H2O in the compressed air. To obtain nitrogen from the air we breath the process dries the nitrogen, removing the H2O, thus reducing the oxidization. If one were to put an air drier on ones air compressor the same results would occur (as well as air loss decrease and mitigation of temperature induced expansion and contraction in the tire). As well most shops use the same air to fill tires that is used to run their air tools and introduce oil into the system which again has diliterious effects on the rubber of the tire so it would follow to have a dedicated air system for tire infaltion and most if not all the advantages of nitrogen fill go away.

  3. Thomas | September 12, 2009 at 09:00AM
    I can see why airplanes and race cars would use nitrogen, all the friction on the pavement, would get the tires heated up very quickly. What happens to tires filled with nitrogen that are operated in below freezing conditions. Lets say Alaska or other states where in the winter the temperatures are well below zero for weeks at a time?

  4. Dwain | September 14, 2009 at 02:50PM
    What effect does this have on the average consumer who does follow a regular check on tire pressure? I have heard reports where the TPMS indicator went on on a new car with low-profile tires; the dealer informed the consumer that in order for the warranty on the tire and TPMS to remain intact, the consumer had to schedule a visit - at the cost of $50 for the service call and needed to be scheduled in advance. Additionally, I own two 2001 autos (Dodge pickup and a Volvo sedan), that do not have TPMS nor nitrogen-filled tires? Is there over-the-counter solutions to auto-compressors or service-station compressors that allow me to fill my tires when the pressure does get lower than I like? That's another cost-obstruction to the proliferation of nitrogen (having to go to a specific mechanic or dealer and the lack of home-automotive remedies). What concerns me is the Kia dealer telling the consumer (my father) that the tires MUST be filled with nitrogen or the warranty on the TPMS would be immediately invalidated.

    Thank you.

  5. Mike | March 24, 2010 at 09:10AM
    Dwain, you ask "What effect does this have on the average consumer who does follow a regular check on tire pressure?" There would be no noticable benefit at all, really. Frankly, if every consumer did as their auto manual suggests doing once a month whioh is check and adjust the tire pressure there would never be a discussion about the benefits of nitrogen in a passenger vehicle. However, it's not so convenient for the average motorists, which is the majority of motorists, to do the monthly checks and adjustments. Not many have easily available air supply in the garage. The gas stations are not full service and the air hoses have been moved from beside the gas pump to the edge of the parking lot where the motorist may have to dig for a couple of quarters to use the station. The reality is that most motorists today get the checks and adjustments at oil change which aren't exactly 3,000 miles anymore meaning there is more time passing between checks and adjustments. That's where the benefit of nitrogen becomes realized; over time. Or, the time lapse between oil change. A savvy nitrogen dealer would recommend having their customer stop by each month for a quick check and adjustment. Oh, and while they have the car, check for other current or future problems such as wipers, light bulbs and brakes even, if time permits. There are a few nitrogen programs that help the dealer remind their customer to stop by for that deal and several have nice insurance and assurance packages for their customer's benefit for switching to nitrogen. Further on the nitrogen subject, the typical car buyer purchases a car further away than their local service, or, independent shop. That does cause a slight problem for the car owner who, whether they reaalize it or not, paid for having the nitrogen in the first place. I would think it is embarrasing to tell the car owner that the pressure can't be adjusted while there for a routine oil change due to the lack of nitrogen. However, the shop withou

  6. Jared | March 08, 2013 at 04:23PM
    Michael oxidation is caused by oxygen, hence the name oxidation. Water can speed the process due to the oxygen in water. Oxygen is a very corrosive element. Removing as much oxygen as you can does help reduce corrosion on any surface.

  7. Dave | March 15, 2013 at 01:16PM
    Your first claim "Tires hold their psi longer ... " It is true that the Nitrogen molecule is larger, but come on ! We drive our vehicles not park for a year. Tire loss is from three ways ! Bead leak, valve or a puncture. These are the losses that take place in the real world and Nitrogen will not prevent any of that.

    Claim #2 "Nitrogen runs cooler than air". That is false. The problem is the next statement, Nitrogen temperature DOES fluctuate. It simply does does not expand and contract as other air molecules therefore maintaining a stable air pressure.

    Claim #3 Oxidation is reduced simply because the Nitrogen is dryer from the processing of filtering it which removes most moisture. Having an air dryer on your system would nearly eliminate any touted reason to have Nitrogen. Wheel corrosion especially aluminum is more due to outside contaminates than inside.

  8. alpio | March 15, 2013 at 02:25PM
    Nitrogen is strictly a money generating opportunity ... does is benefit yes is it necessary NO Now if you really want to help the customer sell more alignments and have your customer come to you for FREE tire rotation and YOU the expert check out there tire pressure and adjust the air up or down depending on there driving habits..

    Its call SERVICE..

  9. Carl | March 18, 2013 at 07:17PM
    The plain fact of nitrogen is that we have been running on it for YEARs..

    Take your average air blend of compressed air 80%N 20% everything else. When you check your tire pressure that next month and it went from 32psi to 26psi, you lost your 20% of everything else. What remained was your Nitrogen. When you inflate again your tire now contains 96% nitrogen. This pattern continues until the air in your tire is nearly 99.63% nitrogen, actually more than a normal N fill. Wasting money on N is exactly that.

  10. John | June 11, 2013 at 10:06AM
    Rubbish! Nitrogen is just another sweet upcharge for local tire merchants. I check my tire pressure once a month on my Audi, and I have yet to wear one out from the inside. I'll bet if someone told you they had filled your tires with N, you would never know the difference if they had used plain old compressed air.

  11. Matt | September 07, 2013 at 06:09AM
    I'm confused. "Nitrogen is a larger molecule" according to the article. It has an atomic weight of 14 and is generally (99.6%+) found as a diatomic molecule with a molecular weight of 14x2=28. Oxygen has an atomic weight of 16 and is also primarily (99.7%+) found as a diatomic molecule, thus having a molecular weight of 16x2=32. Nitrogen also has smaller covalent and van der Waal's radii. So, I don't buy the "nitrogen doesn't leak out because it is bigger" argument. I will concede that oxygen is corrosive, but it seems silly to protect one side (the inside) of the tire from oxidation while the other side sits in "oxygen-rich" air (and moisture) all the time. It appears that there are some, if poorly defined, reasons that it increase efficiency, but notice that the calculations have to be heavily skewed in order for nitrogen to show a benefit. You can save a lot more by driving 60mph instead of 70 or 75 mph and simply keeping your tires inflated properly.

  12. Morry | October 18, 2013 at 11:39AM
    Being involved in this industry for 35 years I think for passenger tires this is a waste of time and money, For truck and OTR it's still a waste of time and money especially if you attempt to do it right. The new tire pressure monitoring systems tell you what's in your tires, keep the right amount in your tires and you will not have any problems! Nitrogen is a profit model only. Carl above you are way off...

Post a Comment

First Name:
  Last Name:



Receive the latest MTD eNews in your inbox!

Signup Sign up for our Enews and receive the latest news, trends, and product information right in your e-mail inbox. Join Today!

View the latest eNews:
Monday  |  Tuesday  |  Thursday Edition  |  CTD Online  |  Auto Service

Be Informed : Stay Current
Free Weekly Hotwire E-News