Dear Bree,

I bought a set of new tires from RNR last week, and the nice guy who helped me asked if I wanted to fill them with nitrogen for $20.  I asked him what the heck he was talking about—since when don’t you just fill them up with regular, old air?  He told me that nitrogen has lots of benefits like better fuel economy and longer tire life, so I told him to go ahead.  Can you give me a little more detail on this whole nitrogen thing?

A Little Lost in Orlando

Dear Lost,

I think you made a wise choice, even if you weren’t quite sure what you were agreeing to.  A word of advice:  Don’t be afraid to ask one of our guys (or gals) for more information if you don’t understand something.  We’re well-trained here at RNR, and we know what we’re talking about.  We’d love for you to know what you’re talking about too—so just ask!

Let me tell you a little more about nitrogen and why we recommend it.  The air you breathe is 78 percent nitrogen, a little less than 21 percent oxygen, and the rest is water vapor, CO2 and some other gases, so when you put “regular, old air” in your tire, you’re getting plenty of nitrogen—but you’re also getting oxygen and water vapor.  Oxygen is more likely than nitrogen to migrate through the rubber of your tire, so if you have just nitrogen in your tire, then your tire pressure should stay more stable than if you filled your tires the traditional way.  Stable tire pressure means longer tire life and better performance.  Ambient temperature changes cause a change in tire pressure (for every 10F degree change, there is 1.9% change in pressure) with traditionally-filled tires and nitrogen-filled tires, but the difference hinges on that water vapor.  Water (whether present in a vapor or liquid form) causes even more of a pressure change with temperature fluctuations (and can also cause the corrosion of steel or aluminum rims).

If your tires are nitrogen-filled, water vapor won’t be a problem.  If you’re getting pure nitrogen, then you’re getting dry nitrogen.  Most tires will need to go through a process of filling and purging several times in succession to rid the tire of oxygen, and thus water vapor.  We can take care of all of that here at RNR, and we do it for free when you buy or rent a new set of tires with us.

We think you’ll see a difference in the performance and the life of your tires with nitrogen fill; some studies have shown a 25% increase in tire life using nitrogen (in addition to better gas mileage!).  Nitrogen is actually used in some pretty important tires:  NASCAR uses it to cut down on tire replacements during races, and airlines use it to extend the life of tires on their airplanes!  We’d really like to know what you think as time goes by.  Think you could keep us updated?  In the meantime, go forth and spread the nitrogen word!  You are officially informed!

Bree