by Kevin Lamb

Created on: December 11, 2008   Last Updated: December 14, 2008

If you want to run pure nitrogen in your tires you'll have to do a little more than have them filled at your local tire dealer. The unmounted tire already holds 14 psi when it goes on your wheel. Unless the tire dealer mounts your tire in a vacuum (which is unheard of) the percentage of nitrogen is already diluted when your tire is mounted from the start. The percentage of dilution will also depend if the tire was filled with "pure" industrial grade nitrogen.

Tires which are filled with air are already running 78% nitrogen as it is. The remainder of what's in the tire is 19-20% oxygen and the rest is gases. So if you change over to nitrogen you're only going to possibility gain 8 to 10% of nitrogen if you're lucky.

The filling of tires with nitrogen has now become common practice in the tire replacement market. This is another service for the tire dealers to offer for making more money while promoting safety at the same time. This is not a new idea, it has been kicked around since the mid seventies.

The benefit of using nitrogen includes "the potential for reducing air loss, help prevent tires from overheating, and promotes optimal tread life." It's also been reported of a 3.0 percent gain in fuel mileage (in some vehicles). Nitrogen also reduces rubber aging of the tire (on the inside) and lessons wheel erosion.

The National Highway Traffic Safety Administration (NHTSA) has "seen reduced aging of tires filled with nitrogen." But the manufacturers say; "they don't see the need to use nitrogen," which usually cost around five dollars a tire to switch over to using nitrogen.

Airplanes, race cars and the military use nitrogen so why shouldn't we? The main reason the military uses nitrogen is because it is inert. It does not promote corrosion and poses no combustible hazard. The military's SR-71 runs 600 psi in its tires. A blown tire with a hot wheel well could cause a serious fire, and nitrogen would quench this fire.

The life of the tire is air pressure along with balancing and rotation. Oxygen is also several times more soluble in rubber than nitrogen, which causes the tire to break down along with heat; which then cases "water vapor." This water vapor is where the problem begins. Less heat in the tire is generally good for tire wear and durability. Therefore, it's better on the tire (on the inside) to have "less water permeating it, while the tire is working and getting hot; due to the flex of the tire while driving."

Industrialized nitrogen not only has less oxygen

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