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When most people inflate their tires, they go with plain old compressed air. It’s cheap, widely available, and works just fine. But there is a pricier alternative: nitrogen-filled car tires. Since there’s a lot of confusion surrounding this gas — it’s in the air we breathe — we set out to answer the most common questions about tires filled with nitrogen.
Proponents claim that filling your tires with nitrogen boosts gas mileage, reduces air loss, and extends a tire’s life. In a Consumer Reports study, the publication found that the difference between nitrogen- and air-filled tires was modest, with nitrogen reducing about 1.3 PSI in pressure loss. “Our test showed that while nitrogen has some advantages, both nitrogen and air-filled tires lose pressure over time,” said Ryan Pszczolkowski, Consumer Reports’ tire project leader. “It is important that car owners routinely check their tire pressure.”
Similarly, the National Highway Traffic Safety Administration found that nitrogen extends a tire’s life by limiting oxidation (a chemical reaction), though rolling resistance — which affects fuel economy — was more or less the same. Put simply, filling your tires with nitrogen may offer a slight edge when it comes to air loss and tire life.
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You can safely mix regular air and nitrogen in tires, especially since air is already around 80% nitrogen. That said, you won’t see the benefits of nitrogen-filled tires if you mix the two.
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Dealers, tire shops, and Costco offer nitrogen inflation stations. While some places will charge you a premium to check your air pressure and add nitrogen, Costco’s nitrogen stations are free — and you don’t even need a membership to use them. Since it’s a membership perk, it’s a bit of a gray area, but the air pressure stations don’t require any form of payment or identification.
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On car enthusiast subreddits, the consensus is that nitrogen isn’t worth the extra dough. “It makes your car faster because of the weight reduction caused by an emptier wallet,” one Redditor jokes. Another top commenter stressed that investing in a tire gauge was far more important. “While [nitrogen] can offer marginal improvement on pressure loss and fuel mileage, the savings is more than offset by the additional costs,” they write. In other words, it’s far more important to check tire pressure regularly.
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Probably not. Since the benefits are modest and the cost is potentially high, you’re better off inflating your tires with whatever is closest and cheapest. Instead, you should worry more about checking your tire pressure once a month and inflating them according to your vehicle’s recommended PSI, which is posted on the inside of the driver-side door.
