The Truth About Filling Your Tires With Nitrogen

Michael Martineck
by Michael Martineck
the truth about filling your tires with nitrogen

Jet planes, armored personnel carriers and racecars all have nitrogen-filled tires. So it’s got to be cool, right? I mean, I wish my Honda Odyssey minivan was more like an F-22 in some way. Or in any way. Anyway, is it worth an average five bucks a tire to stuff your rubber with the seventh element? For the majority of American drivers– those who do not routinely drive through flaming pools of fuel, off-road on dunes hotter than Scarlett Johansson’s hips or hit 200mph on the straight-aways– the answer is a simple “no.” Yet thousands of vendors are setting up nitrogen pumps and enticing people to pop open their stems. What’s the point?

Purified nitrogen is more stable and less corrosive than a compressed version of the air we breathe. By its lonesome, nitrogen clumps in large molecules. Even better, it’s not oxygen, which is the root of oxidation, which eats rubber just like steel, just not as dramatically or visibly. All of this means the gas has two things going for it.

First, compressed air is a blend of oxygen and other tire degrading contaminants, including water. Your tires should last longer filled with pure, dry, nitrogen gas. Second, nitrogen’s larger molecules are less likely to seep through rubber. Nitrogen-filled tires delivers more consistent inflation pressure– especially under temperature fluctuations. Studies suggest nitrogen-filled tires will remain properly inflated three times longer than air-puffed companions.

Nitrogen’s advantages are solid (so to speak)– provided you’re a diligent motorist and nitrogen refills are free. Add some nonchalance and a dollar figure and the benefits evaporate.

Oxygen only accounts for about 21 percent of the ambient air (nitrogen makes up 78 percent). And oxygen is going to eat the outside of the tire– no matter would put inside. And if you don’t drive that much, you’re not getting the air inside all hot and bothered, which increases the decay rate.

In truth, most drivers are going to wear out their tires long before the rubber will decay enough to lower tire performance or safety; those radials will last until much of the gas– any gas– seeps out. I repeat: whether you drive a lot or a little, internal tire degradation isn’t much of a worry.

Proper inflation is the real issue. Under-inflated tires reduce gas mileage. They flatten out, creating more surface area and thus adding friction, which makes the engine work harder. The extra friction, and resulting heat, also increases the chance of a blowout. A properly inflated tire is always safer and more efficient than under-inflated shoes (unless you’re driving across a sand dune).

Nitrogen’s reluctance to leave the wheel is a blessing because it helps maintain tire pressure at optimal levels. Of course, checking your tire pressure once a month does the same thing. AND regular checks get you close to the rubber for a chance of seeing something else that might be going wrong: weird wear, a protruding rail spike, a chunk scraped away by that curb you forgot you hit, etc.

In any case, tire manufactures reckon your tires lose around one pound per month of inflation pressure. There are a ton of variables, but the National Highway Traffic Safety Administration says that maintaining recommended pressure improves the average driver’s gas mileage by three percent. That’s about $50 a year just for paying attention– not to mention the better handling and reliability that come along for the ride.

Yes but– nitrogen is still going to leave the inside of your tires for the big, wide world; just not as quickly as oxygen. A pound’s worth of gas might seep out in three months, rather than one. Meanwhile, the idea that nitrogen-stuffed tires are a fill-it-and-leave-it alternative to air is an inherently dangerous supposition. Drivers still need to get down, stick on a gauge and hear the hiss whether they’ve used air, nitrogen or cream filling. Nitrogen hype can end up doing more harm than good.

Goodyear Tire & Rubber Co. is ambivalent about the use of nitrogen. The Rubber Manufacturers Association says it it’s a good thing– when it’s free. Michelin goes a step further. They recommend nitrogen only for tires used “in high risk environments” like aircraft landing gear and racing.

A quick look at a few of the nitrogen generator manufacturers’ websites can give you an idea what may be driving some of the interest in swapping tire gasses. N2 machines can operate for as little as 25 cents an application. The generators themselves go for as little as four grand. After the first 200 or so nitrogen fill-ups, these things are more profitable than pretzel carts.

As with most things, it’s all about me. I’ve got to be more conscientious about checking and rotating my tires. If I want them to be all they can be, I’ve got to be better. It’s what’s inside that counts-– or, in the case of nitrogen, not. So, to make my minivan more like a fighter plane, I’m looking at other modifications. Possibly chaff.

Also, if your tires suck and you’re shopping for new tires, help support TTAC’s work by doing your research at — TTAC Staff

Join the conversation
2 of 70 comments
  • on Mar 15, 2011

    [...] i read an article about it, pretty dam useless , unless im going blazing fast speeds. The Truth About Filling Your Tires with Nitrogen | The Truth About Cars so back to regular air i [...]

  • SD 328I SD 328I on Jan 03, 2017

    My stock F150 tires from the dealer were filled with Nitrogen. I kid you not, It was almost 4 months before they dropped below 1 pound of pressure. It was almost half the year before I actually added more air. My new tires didn't get this 100% nitrogen, but our normal 78% nitrogen oxygen. I have to adjust the air pressure at least every month now.

  • Sayahh Is it 1974 or 1794? The article is inconsistent.
  • Laura I just buy a Hyndai Elantra SEL, and My car started to have issues with the AC dont work the air sometimes is really hot and later cold and also I heard a noice in the engine so I went to the dealer for the first service and explain what was hapenning to the AC they told me that the car was getting hot because the vent is not working I didnt know that the car was getting hot because it doesnt show nothing no sign no beep nothing I was surprise and also I notice that it needed engine oil, I think that something is wrong with this car because is a model 23 and I just got it on April only 5 months use. is this normal ? Also my daughter bought the same model and she went for a trip and the car also got hot and it didnt show up in the system she called them and they said to take the car to the dealer for a check up I think that if the cars are new they shouldnt be having this problems.
  • JamesGarfield What charging network does the Polestar use?
  • JamesGarfield Re: Getting away from union plantsAbout a dozen years or so ago, Caterpillar built a huge new engine plant, just down the road here in Seguin TX. Story has it, Caterpillar came to Seguin City council in advance, and told them their plans. Then they asked for no advanced publicity from Seguin, until announcement day. This new plant was gonna be a non-union replacement for a couple of union plants in IL and SC, and Cat didn't want to stir up union problems until the plan was set. They told Seguin, If you about blab this in advance, we'll walk. Well, Seguin kept quiet as instructed, and the plan went through, with all the usual expected tax abatements given.Plant construction began, but the Caterpillar name was conspicuously absent from anywhere on the site. Instead, the plant was described as being a collective of various contractors and suppliers for Caterpillar. Which in fact, it was. Then comes the day, with the big new plant fully operationa!, that Caterpillar comes in and announces, Hey, Yeah it's our plant, and the Caterpillar name boldly goes up on the front. All you contractor folks, welcome aboard, you're now Caterpillar employees. Then, Cat turns and announces they are closing those two union plants immediately, and will be transporting all the heavy manufacturing equipment to Seguin. None of the union workers, just the equipment. And today, the Caterpillar plant sits out there, humming away happily, making engines for the industry and good paying jobs for us. I'd call that a winner.
  • Stuki Moi What Subaru taketh away in costs, dealers will no doubt add right back in adjustments.... Fat chance Subaru will offer a sufficient supply of them.