I have a confession: I am a tire snob. With almost 60 years in the “car wars” as a master technician and vocational educator, there are three safety systems on any car I work on (especially my own) where I refuse to compromise: brakes, steering and suspension, and tires.
When the tires on my SUV began to dry rot, the tire manufacturer replaced them under warranty. The tire shop where I took my SUV to have the tires replaced suggested filling the new tires with nitrogen to help prevent further dry rot. I figured it was an “upsell” (as were the new tire valves, plus the “hard sell” for the road hazard warranty), but since I was getting four new tires for free, I let them do it for the $30 fee.
Unfortunately, over the next four years, my SUV was driven very little. The replacement tires, with tread that was almost brand new, developed a nasty case of dry rot—again replaced under warranty. In my case, the nitrogen didn’t help. So, how do you decide whether to use nitrogen in your tires— is it ever worth it? Read along as experts in the field separate myth from fact on using nitrogen in your tires
Benefits of Nitrogen
The selling points are fairly straightforward: nitrogen-inflated tires maintain steady air pressure even during seasonal temperature fluctuations, improve fuel economy, extend tire life, and enhance driving safety. “Nitrogen molecules are larger than oxygen molecules, so in theory, the larger nitrogen molecules are supposed to leak more slowly,” says Jim DeLeo, of Hunter Engineering Company. “Nitrogen also does not contain moisture, which supposedly reduces corrosion and oxidation inside the tire and wheel.”
What Does the Science Say?
“Nitrogen used in service garages, as is regular shop compressed air, is usually filtered and dry, but still in regular driving, the difference [in overall tire performance] is very slight,” says William Fletcher from car.com.uk.
Scientific testing from multiple sources shows that the benefits of tires inflated with nitrogen may be real but negligible:
- Consumer Reports conducted a 12-month test of 31 nitrogen‑filled tires. Those tires lost 2.2 psi, while traditional air‑filled tires lost 3.5 psi, a difference of just 1.3 psi over an entire year. Consumer Reports added, “Our test showed that while nitrogen has some advantages, both nitrogen and air-filled tires lose pressure over time. It is important that car owners routinely check their tire pressure.”
- The National Highway Traffic Safety Administration’s (NHTSA) tests found that nitrogen slows pressure loss slightly, while also reducing oxidation; however, this reduction is not enough to affect real-world tire life or rolling resistance. The report asserted, “Even slight contamination of the tire inflation gas with compressed atmospheric air during normal inflation pressure maintenance may negate the benefits of using nitrogen.”
- AAA testing noted that nitrogen-filled tires did not eliminate temperature‑related pressure changes and didn’t make tires maintenance‑free. According to AAA, “Since nitrogen does not completely eliminate temperature-related pressure changes under normal driving conditions, it is of little benefit to vehicle owners who properly maintain their tires.”
- “If you understand that air is already 78 percent nitrogen, and it’s virtually impossible to evacuate all of the air from a tire assembly. That makes it impractical to try filling a tire with 100 percent pure nitrogen,” said DeLeo. “Mixing air and nitrogen is safe, it just reduces the nitrogen’s purity and any of the small benefits that may come with it. DeLeo added that when it comes to dry rot, “Nitrogen protects the inside of a tire. A tire’s outside is exposed to heat, cold, UV rays, and Ozone that cause rubber to degrade.” Other causes of dry rot include harsh tire and wheel cleaning chemicals, road salts or a car sitting idle for an extended period without being moved.
When Nitrogen Makes Sense
Racing cars have used nitrogen-filled tires for years, primarily due to stability during extreme temperature swings and because nitrogen doesn’t support moisture or combustion. Many commercial fleets also use nitrogen-filled tires. While an individual driver normally sees minimal economic gain when using nitrogen-filled tires, the savings can be significant when multiplied across hundreds of vehicles.
Of course, if you never bother to check your tire’s air pressure or wait until the tire pressure light comes on, then going with nitrogen-filled tires would make sense.
When Nitrogen Probably Isn’t Worth It
If you use regular air and you check your tire pressure monthly, nitrogen usually doesn’t justify the cost. The total air pressure loss difference is insignificant. In addition:
- All the tests show nitrogen did not substantially improve fuel economy when pressures are properly maintained.
- Nitrogen does not prevent punctures, major leaks or valve stem issues. In these situations, “both gases will leak equally,” says Fletcher.
- Nitrogen does not typically increase tire life under normal driving conditions.
- Online tire retailer, Tire Rack may have said it best, “Rather than pay extra for nitrogen, most drivers would be better off buying an accurate tire pressure gauge and checking and adjusting their tire pressures regularly.”
FAQ
How do I know if my tires can be filled with nitrogen?
“Any modern tubeless tire can be filled with nitrogen,” says DeLeo. Tires today are manufactured to exacting standards, making it more difficult for both nitrogen and air to seep through microscopic spaces that exist between a tire’s rubber molecules than in previous tire generations. If you want to switch to nitrogen, your shop must purge (inflate, then deflate) the tires with nitrogen several times to reach a purity level of 95 percent or greater. Although not required, install green valve stem caps (with N2 logo), which indicate that your tires are filled with nitrogen.
Is nitrogen environmentally better?
No, not really. Our breathable air already contains 78 percent nitrogen and is an essential necessity for all life on earth. Additionally, nitrogen as a fertilizer plays a crucial role in farming and agricultural production. However, nitrogen oxides (NOX) is an environmentally damaging tailpipe emission and a major contributor to air pollution, increasing health risks. “Properly inflated tires can increase fuel economy, reducing emissions (smog) over time,” says Fletcher, which can help the environment.
Experts
- Jim DeLeo is the Northeast Division Manager for Hunter Engineering Company.
- William Fletcher MBE (Order of the British Empire) is the CEO of Car.co.uk a UK-based online car-selling and automotive services platform.
Resources
- AAA Automotive: “Top 4 Myths Vs Facts About Using Nitrogen To Inflate Car Tires“
- Biology Insights: “Is Nitrogen Good or Bad for the Environment and Your Health?“
- Car Buzz: “Nitrogen In Tires: Understanding The Benefits“
- Consumer Reports: “Should You Use Nitrogen in Your Car Tires?“
- NHTSA: “Use of Nitrogen Gas in Tires“
- Tire Rack: “Should I Use Nitrogen In My Tires?”
The post Should You Use Nitrogen In Your Tires? Experts Weigh In appeared first on Family Handyman.
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