Keeping our tires in good working condition is an important responsibility for the everyday driver. To get the most miles out of your tires, routine maintenance and making sure your tires, suspension, and vehicle alignment can help keep them rolling for a long time. However, there seems to be a claim floating around that putting nitrogen instead of air into your tires will prolong their life and improve your driving safety. That isn't necessarily true. Nitrogen in your tires doesn't really make that much of a difference, but there are arguments for and against it.
The air that makes up the atmosphere and the air we breathe has a very special balance. 78% of the air is made up of nitrogen, whereas oxygen makes up 21%, and the other 1% is water vapor, carbon dioxide, and other gases. With so much nitrogen, surely we can spare some for our tires, but are the claims actually true? Does putting nitrogen in your tires prolong their lifespan, increase fuel economy, or maintain tire pressure longer? Let's take a look at the pros, cons, myths, and what owners have to say.
Yes, there may be some benefits when it comes to filling up your tires with nitrogen. All tires lose air over time and can become a little underinflated. This is because the walls of tires are slightly porous, and this allows air molecules to pass through over time. The belief is that, because the nitrogen atom is physically larger than oxygen, it will take longer to leave the tire. Some sources claim that nitrogen-filled tires can last up to 40% longer than tires filled with oxygen, or will at least have a decrease in air loss by a third. One owner backs this up, "Nitrogen tires require less refills because the molecules are large enough to not leak through the rubber and the pressure changes due to temperature fluctuations are less."
If this sounds like a good idea, consider the costs. To fill up your tires with air at a gas station or other service station may not cost more than a dollar, but the same can't be said for nitrogen. Some facilities will charge from $30 per tire. A top off may cost less, about $5 or $7 per tire, but do the math and it adds up. Moreover, some auto dealers will claim 100% nitrogen-filled tires are better, but it's one of the fake dealer fees they will try to tack on to make more money off of you. As another car owners exclaims, "Biggest scam in the auto industry!"
There is a common myth that nitrogen-filled tires will also increase fuel economy, but the fact is, any tire that is properly inflated (or not) will have an effect on your mileage. Like all myths, it's just a rumor. So let's bust some more myths.
There is a myth that nitrogen isn't affected by temperature changes, and will keep tire pressure more consistent for the reason stated above about their atoms being larger. But the facts are molecules of both air and nitrogen will contract in colder temperatures and expand in warmer temperatures. Another commonly held belief is that nitrogen can help prolong tire life because it reduces the amount of water vapor that can be found in a tire, degrading it over time. In truth, most compressed air systems have a moisture separator that limits the amount of water vapor that makes it into the tire.
Even with these myths busted, many still circulate around the automotive industry. Interestingly enough, though, some advice about nitrogen-filled tires that sound like a myth are actually true. For instance, nitrogen can improve the performance of some vehicles, like sports cars. This is especially true for race cars.
They're one of the niche vehicles that can actually greatly benefit from nitrogen-filled tires. As Reddit user SpeedHAM79 notes, "Nitrogen is completely a sales gimmick for regular cars. For racing cars it's a different matter as "Shop Air" that is used to inflate tires is typically at 100% humidity." The same can be said for semi-trucks and even the space shuttle. So, not all you hear about nitrogen is true, but if you have money to spare, you can reap some of the benefits if you own a sports car. And if you don't, we have a list of some of the best entry-level sports cars you can buy.