tires March 24, 2017

Nitrogen vs Regular Air in Tires

You may have heard that some auto shops fill their tires with nitrogen instead of regular air. What exactly does that mean, and what are the benefits?

The composition of air that’s usually used to inflate tires is roughly 78% nitrogen, 21% oxygen, and 1% miscellaneous gases. While the majority of this normal air is nitrogen, there is still a decent amount of oxygen, which is much less desirable when it comes to inflating tires. Here’s why:

Nitrogen is a “slow” inactive gas.

This means it’s much tougher for nitrogen molecules to escape the tiny spaces between rubber molecules, thus maintaining tire pressure for a longer time. Oxygen is a “fast” active gas, so it’s easier for air to escape the tire when it has higher oxygen levels.

Nitrogen is a dry gas.

This means it won’t support much moisture inside the tire. On the other hand, oxygen is a major component of water (mixed with hydrogen = H2O), and moisture inside can contribute to corrosion of the steel/metal parts built into the tire.

In general, nitrogen filled tires could maintain air pressure more consistently, and natural pressure loss via rubber permeation could be reduced by up to 1/3. It may also reduce the risk of corrosion to inner parts of the tire, like the beads, belts, and sidewall reinforcements. Extreme tire applications (like airplanes, military vehicles, industrial equipment, and racing cars) will see the benefits of using nitrogen the most. A lot of this has to do with temperature fluctuations affecting the tire pressure a little less (due to less moisture inside the tire).

While there are obvious benefits to using nitrogen in tires, there are a few things to keep in mind:

  • Nitrogen generators, if used properly, will usually get the air inside a tire to roughly 93-95% nitrogen. Because it’s not pure nitrogen, there is still oxygen inside, just at a lower percentage. Atmospheric pressure will also push oxygen and moisture into the tire from the outside, so the inside of the tire will never be totally free from moisture.
  • Nitrogen is still a gas, and as such, it will still be affected by outside temperature. Air still needs to be added to tires when the temperature drops, typically in the late fall/early winter months.
  • Using nitrogen in tires is never a replacement for a good quality tire pressure gauge kept in your vehicle, or monthly air pressure checks.
  • If your tire pressure is low and you can’t find a nearby location that offers nitrogen fill, it’s always best to get regular air and adjust it back to a nitrogen fill when possible. It’s never ideal to use your tires underinflated.

Maintaining proper air pressure (nitrogen or regular) in your tires is not only safe, but it also increases tread life, fuel efficiency, and helps your tires wear evenly. You’ll be happy to know that we fill tires with nitrogen at Wiygul Automotive Clinic. Stop in to any of our 8 locations and our expert techs will gladly inspect, repair, or replace your tires with precision!

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