What's the Scoop on Nitrogen Inflation? - Greater Cincinnati Automobile Dealers Association
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What’s the Scoop on Nitrogen Inflation?

            For years nitrogen inflation has been used on tires that handled high speeds and heavy weights.  Vehicles made for racing, aircrafts, and heavy-duty equipment like earthmovers and mining vehicles have had nitrogen in their tires.  But it wasn’t until a few years ago that nitrogen inflation began being offered on personal vehicles as well.  Since then, there’s been more of a presence of green caps on the end of some tire tips, which means that those tires are filled with nitrogen.  What does that mean, and what’s the purpose? Nitrogen inflation is one of the ongoing mysteries of the automobile industry.  What benefits does it have, and, is it worth it?

            Tires themselves don’t carry the weight of the vehicle, rather, the pressure of the air inside the tire.  With nitrogen inflation, the air in tires should be between 93 and 95 percent nitrogen.  This number can only be achieved, however, if all air except for a few psi are taken out of the tires, and new air is put in.  To get the greatest possible percentage, it’s best to repeat this process another one or two times.  The air that typically fills tires of personal vehicles consists of 78 percent nitrogen, 21 percent oxygen, and 1 percent miscellaneous.  The pressure in tires is measure by psi (pounds per square inch).  It’s estimated that with regular air, tires lose about 1 psi of pressure each month.  This is because air escapes through microscopic gaps that form between the rubber molecules of the tires every time the tire rolls, a process called permeation or diffusion.  

            Nitrogen has been used in other vehicles for years primarily because it’s considered a “safe” gas.  It doesn’t support moisture, and it isn’t flammable.  The lack of oxygen in the tires prevents oxidation, and it takes longer for air to escape from the tires.  Because of the lack of moisture, there’s a smaller chance of rust and corrosion of a car’s wheels. 

            So, should you get nitrogen inflation in your car?  The answer is that it depends.   Nitrogen is still a gas, which means that changes in temperature will still affect the pressure.  During winter months, the pressure will still drop.  Some claim that nitrogen inflation is a replacement for monthly tire pressure checks.  This is not true.  Even though nitrogen inflation can slow the process of losing pressure, it is only by about 1/3.  You should still get your pressure checked every month. 

            Nitrogen provides some benefits, but if you are a frequent driver, your tires will probably need replacement by the time you would actually see any of them.  Nitrogen inflation is good for cars that aren’t driven a lot.  This could be a car of collectors, RVs, and others such as snow tires.  However, it doesn’t hurt to inflate your tires with nitrogen, as it can provide some minimal benefits.  If you find a place that offers free nitrogen inflation, why not give it a shot?  If it’s not free, a reasonable price that would be worth trying is about $5 per tire.  If it’s much more than that, it’s probably best to turn around and walk away.