A car service representative recently tried to sell me nitrogen tire inflation for $10.00 a tire. It would pay for itself in no time, he said, because nitrogen-filled tires get better gas mileage and wear less. Well, this “Frugal Frannie” was skeptical. So I did some research.

I checked out the Get Nitrogen Institute's savings calculator. I typed in my stats: 12,000 vehicle miles per year; $80 tire replacement; $3.60 per gallon of gas (the national average as of early June 2012); 18 miles to the gallon. The calculator determined my yearly savings (and I was surprised):

  • Improved mileage would reduce fuel costs by $83.40.
  • Increased life of tires would save $20.19.

Total savings per year: $103.59*
*Based on maintaining proper tire pressure, according to manufacturers' recommendations.

More than $100 a year seemed too good to be true. And it is. The Get Nitrogen Institute is sponsored by companies such as Parker Hannifin and Branick Industries, who sell nitrogen tire inflation products.

It turns out the air we use to fill up our tires is already made up of about 78 percent nitrogen and 21 percent oxygen. (That’s 99 percent for those keeping track.)  According to Consumer Reports, special nitrogen tanks used to inflate tires produce about 95 percent nitrogen — a mere 17 percent difference from the free air you are already using. Most technicians don’t know they need to completely empty tires and refill to get to the 95 percent level! Consumer Reports  also says a year-long air-pressure experiment revealed nitrogen-filled tires performed about 3 percent better than air-filled tires.

The Bottom Line: Nitrogen-filled tires SLIGHTLY outperform air-filled tires. A $10.00 per tire service isn’t going to save you much money, and certainly not $100 a year. If you can get the service for free, go for it.  If not, stick with regular old free air.

Under Pressure: Pass Up Nitrogen-Filled Tires