One of the most important steps that a driver can take to ensure both the safety and longevity of their tires is to understand how to check tire pressure. Furthermore, properly inflated tires, and checking their inflation at least once a month, can help boost fuel economy, reduce tread wear, decrease your car’s stopping distance, and decrease the chances of a catastrophic tire failure such as a blowout.
Despite this, a report by the U.S. Department of Transportation’s National Highway Traffic Safety Administration shows that 75% of American drivers don’t know how to properly check for optimal tire inflation and almost 50% of drivers don’t check their tires’ pressure regularly. To address this problem, some tire dealers have begun offering nitrogen as a tire fill instead of air. Let’s take a closer look at how nitrogen functions in tire inflation and why some drivers might find nitrogen tire inflation to be preferable to air.
How Does Nitrogen Inflation Affect Tire Inflation?
The greatest benefit of nitrogen tire inflation compared to standard compressed air—or the type of air you’d typically find at the air pump at your local gas station—is that nitrogen may help keep tires inflated longer. It’s a matter of basic chemistry. Standard compressed air is composed of the same air we breathe. This means it’s about 78% nitrogen, 21% oxygen, and 1% a mixture of other gasses such as carbon dioxide. Compressed nitrogen for tire inflation is much more homogenous, generally between 93-99% pure nitrogen with the rest comprised of an admixture of other gasses.
Nitrogen molecules are larger than oxygen molecules, meaning that it’s more difficult for nitrogen to leak out of your tires through the innerliner membrane used to retain air. This natural process of air escaping is known as permeability. While both nitrogen and oxygen can and will eventually find their way through the tire’s innerliner, it can take up to six times longer for nitrogen verses oxygen.
Also, the compressed air in your tires contains water vapor, just like the air we breathe —this is what’s called humidity. In tires, this water vapor has two effects. First, it can accelerate the oxidation process. Secondly, water vapor pressure varies a lot with changes in temperature. This can result in increases (or decreases) in your tires’ pressure. Compressed nitrogen in tires, on the other hand, is dry, making it more stable than standard compressed air, even at the higher temperatures tires are subject to at highway speeds.
What are the Benefits of Utilizing Nitrogen in Tires?
There are a few. First, nitrogen inflated tires may help save money on gas. According to the U.S. Department of Energy, “Under-inflated tires can lower gas mileage by .3% for every 1 PSI drop in pressure on all four tires.” This translates to a fuel economy benefit of up to 3.3% improvement of your gas mileage or $.07/gallon fuel savings. Because nitrogen may help keep your vehicle’s tires inflated longer, you may see some savings at the pump.
Additionally, properly inflated tires can prolong their longevity and help them perform better. When your tires are kept at the correct tire pressure, their handling and traction are at their best.
Are there Negatives to Using Nitrogen for Tire Inflation?
For many drivers, compressed nitrogen for tire inflation can be a good choice, but there are some drivers who might find standard compressed air to be the better option. First, nitrogen is more expensive than compressed air, ranging anywhere from $3-10/tire depending on the dealer and the size of tire. That’s a much higher up-front cost, but the increased time tires remain at their correct pressure may make it worth the price to the vehicle owner.
Additionally, though nitrogen is available much more widely than it once was, utilizing nitrogen-filled tires can still mean some extra planning for many drivers. Whereas with standard compressed air you’d be surprised not to find it available at a gas station, with nitrogen tire inflation you’ll want to familiarize yourself with your nitrogen dealer options.
Other Questions about Nitrogen Tire Inflation?
Let’s look at some other frequently asked questions about nitrogen tire inflation and get them answered.
1. What tires does nitrogen work with? Can I use it now?
Dry compressed nitrogen air can be used in any type of tire at any time and in all driving conditions. In fact, as we learned earlier, nitrogen is a component of standard compressed air, so your tires already have some nitrogen in them already.
2. Will nitrogen work with my Tire Pressure Monitoring System (TPMS)?
You won’t notice any differences in your TPMS if you switch to nitrogen in your tires because it works the same as standard compressed air with your TPMS.
3. How much nitrogen should I put in my tires?
There is no difference between standard compressed air and compressed nitrogen when filling your tires. Refer to your owner’s manual or the tire specs for the Pound per Square Inch (PSI) for your specific tires.
4. Will nitrogen work in my tires in wintertime/summertime?
Nitrogen works just as well even when weather becomes more extreme. Similarly to tires that are inflated with standard air, tires inflated with nitrogen will experience pressure changes with the temperature fluctuations, meaning tire pressure needs to be checked when the thermometer either drops or rises significantly and it is more likely during these fluctuations that your tires will need to be topped off with extra air.
5. Does elevation impact how well nitrogen works in tires?
Nitrogen maintains the same benefits even when driving at higher elevations. However, like tires inflated with standard air, when driving from lower elevations to higher elevations, nitrogen-filled tires will undergo an increase in internal pressure. This increase will dissipate when returning to the original elevation.
6. Do I still need to check my air pressure?
Yes, even when you’re utilizing nitrogen, tire pressure still needs to be checked regularly. Even though nitrogen is less permeable than oxygen, it will still leak out from your tires, albeit more slowly.
7. Where do I get nitrogen for my tires?
While it is possible to buy nitrogen in canisters that you can keep at home for personal use, you’ll most likely want to have it installed by a service center. The Get Nitrogen Institute maintains a nitrogen dealer locator that can help you find your nearest retailer.