Fuel Economy Tip - Fill Your Tires With Nitrogen?
Fill your tires with pure nitrogen as opposed to filling them up with "regular air."
The last time I had the tires changed on my car (which was a week or two ago), when I got the receipt back, I noticed a small additional charge for filling my tires with pure nitrogen. I didn't really think much of it at the time, but a few days later I decided to do some "internet investigation" and find out why I was driving around on nitrogen filled tires.
As a side note, yes, I realize I could have just called the tire place, but that would have been too easy.
Anyway, what I found out through my research (here's one site I found) is there is a belief that tires filled with pure nitrogen tend to hold proper tire pressure longer than tires filled with regular air. The theory behind this is because nitrogen molecules are bigger than oxygen molecules, thus less likely to escape the tire.
To be honest, I haven't really noticed much of a difference, but maybe a month down the road when I go to check my tires, I'll be pleasantly surprised to see that my tires have held their pressure.
So, for the time being, I would recommend that if you go out and get a new set of tires in the near future, go ahead and spend the couple extra bucks to try it out. If it doesn't work out, you're not going to be out much, but if it does work out, you stand to save some gas and money.