Unfortunately, Google tends to auto populate Nitrogen Tire Inflation Scam. I clicked on a few of the links, and was a bit surprised by the wide variety of people that think nitrogen filled tires are a scam. There is such a misunderstanding that I thought it may be worthwhile to discuss exactly how benefits are derived from nitrogen inflation.
1. Nitrogen is not a magic gas. Nitrogen, per se, does not provide the benefit. Benefits are yielded from the better pressure retention that nitrogen provides. Better tire pressure provides better gas mileage and longer tire life. NHTSA has said so in the past (search this blog for NHTSA if you don't believe me). Not to mention that proper inflation is safer.
2. A tire regularly topped off with air will see performance similar to a nitrogen filled tire. This is true, assuming the air is dry. That is a big assumption, because the majority of automotive shops do not have a dryer, or one that works properly. Even those that do have a dryer still leave a significant amount of moisture (vapor) in the compressed air. Nitrogen is ultra-dry, so it fluctuates less with temperature buildup during driving. Bridgestone even said so here.
3. Nitrogen is non-reactive. The majority of tire rubber breakdown occurs as oxygen permeates through the sidewall of the tire. A tire filled with nitrogen effectively halts the aging of the tire. This means your tire retains its strength throughout the life of the tire.
4. Maximizing your fuel economy and tire life ARE good for the environment. So, if these can be accomplished with better pressure retention, then nitrogen filled tires are a green offering.
5. As much as we like to pretend we check our tire pressure regularly, the simple fact is that we dont. The Rubber Manufacturer's Association (Tire Trade Group) has said that 80% of people don't properly check tire pressure. Nitrogen, while not eliminating that issue, helps to mitigate its damage.
6. Air is already 79.1% nitrogen, how is increasing it to 93.5% going to make that much of a difference. It is important to remember that 79.1% nitrogen is laden with water vapor. During a typical nitrogen inflation service, that "bad" nitrogen is removed, and replaced with clean, dry nitrogen. No liquid water to cause rusting. No oil. No water vapor to condense out and cause pressure fluctuations. No pipescale or rust to clog your valve stems. A benefit for your tires.
Thats it. A pro-nitrogen tire guy saying that Nitrogen isnt a magic gas? That nitrogen isnt the end all to proper tire maintenance. I have always been of the belief that if the benefits are explained properly, people usually don't have a problem understanding the value of nitrogen.