Nitrogen vs. Air in Tires 

If you’ve ever seen a green cap on a tire’s valve stem, then you’ve probably seen a tire that’s inflated by Nitrogen instead of normal air. 

Regular, compressed air contains about 78% Nitrogen. A Nitrogen Tire Fill will pump air that’s roughly 95% Nitrogen into your tires, but what’s the point of that extra 17% of Nitrogen? As it turns out, that small increase in Nitrogen can impact the lifespan, performance, and safety of your tires. 

Is Nitrogen Better than Air In Tires? 

Flat or under-inflated tires are the real enemy here that can cause damage to your vehicle and ultimately create a dangerous driving environment. Both traditional compressed air and Nitrogen do the job of inflating your tires, and both will require you to check and maintain your tires’ pressure on a routine basis. 

That being said, Nitrogen does have advantages over regular air. 

Benefits of Nitrogen in Tires 

• Nitrogen molecules are larger than oxygen molecules, which means they tend to leak from a tire more slowly. In a study from the U.S. Department of Transportation, researchers found that, “[in a] 90-day static laboratory test, the inflation pressure loss for new tires inflated with nitrogen was approximately two thirds of the loss rate of new tires inflated with air.”
• Tires with a Nitrogen Tire Fill contain less water vapor, which can slow down corrosion and help maintain tire treads. 
• When cold weather hits, air molecules contract, indicating low pressure in your tires. When the weather warms in the afternoon, the molecules expand, refilling the tire. Filling up your tires when the molecules are simply contracted can lead to over-inflated tires when the temperature warms. Nitrogen doesn’t react to cold in the same way as regular air, preventing over-inflation that causes damage to tires. 
• Nitrogen is especially helpful for larger vehicles that put more pressure and stress on tires. 

In short, Nitrogen tires still need routine checks to maintain tire pressure, but you might not need to fill them up as often, and since they don’t corrode as quickly as air filled tires, they offer increased safety and some performance benefits. 

The U.S. Department of Transportation study summarizes things this way, 

“A primary positive result expected from nitrogen inflation may to produce more uniformly maintained tire pressure over time, which would help maintain tire performance properties such as handling, rolling resistance and durability. As seen from the effect of liner composition on IPL, this may be more important for some tire models. Also, there is a strong scientific basis for concluding that reducing the oxygen content of the inflation gas will reduce the internal thermooxidative degradation of the tire, which may aid in retention of durability.”

Can I Put Air in a Nitrogen Tire? (Mixing Nitrogen and Air in Tires) 

There’s no major problem with mixing normal air and Nitrogen in tires, other than that it will dilute the Nitrogen and its benefits. If you have low tire pressure, it’s more important to get air into your tires to inflate them than to make sure you’re refilling them with Nitrogen if you’re not close to a place that can provide a Nitrogen Tire Fill. 

Should I Get a Nitrogen Tire Fill? 

There’s nothing wrong with filling your tires with traditional, compressed air. However, TMT offers Nitrogen Tire Fills that can increase the life expectancy and performance of your tires. In fact, we offer a free Nitrogen Tire Fill on any new tires purchased from TMT so your new tires have the best possible start to their life on the road. 

If you get a Nitrogen Tire Fill, just remember to continue filling your tires with Nitrogen to experience the benefits of Nitrogen in your tires; and even though your tires will deflate more slowly with Nitrogen, you should still check your tire pressure regularly for the safest driving experience.