Seems like a bit of a ripoff

The Oil Change people actually want me to pay $20 for an extra 21% Nitrogen


Well, nitrogen IS expensive, you know...


So I was getting the oil changed in my car not long ago, and I noticed a new "service" offered by the fine folks at the oil change place. They'll pump your tired to the recommended pressure for free, but if you ask, they'll fill them to the recommended pressure with NITROGEN for $5 per tire. My car is of the standard 4-tire variety, so this "service" would cost me $20.

The advantages of nitrogen (so they say) are numerous...including it's lighter than air, dryer than air and keeps pressure stable better than air.


Boy, that "Air" stuff sure sucks, doesn't it?


Sure does. There's a couple things they don't seem to point out when offering this "service" to good and decent paying customers. First, that "Air" stuff that they decry so much is composed of just over 78% Nitrogen already. Even if they were to use ultra-high purity Nitrogen, they'd get to 99.9% nitrogen. That buys you 21.8% extra nitrogen...which is actually pretty cheap to produce and certainly doesn't cost them $5 per tire to obtain.

Second, I didn't ask about this, but I'm reasonably certain that prior to filling your tires with Nitrogen, they do not fully purge out the gas already IN the tire...which for every sane member of the driving public is Air. If I had more time, I'd go through the calculations to figure out what the percentage of Oxygen is in the tires already and find out if they added a certain volume of pure nitrogen, what the residual Oxygen concentration would be. I'm certain it's not negligible. Even if they were to let all the Air out of the tires, getting it down to 0 PSI before filling it with Nitrogen, there would STILL be a measurable volume of Oxygen in the tire...since the tire would still maintain it's shape and not be reduced to a vacuumy pancake.

In short...a big, hearty NO THANKS to the chumps who want me to spend $20 filling my tires with the gas the "Professionals Use." (I'm actually not making that up...it was one of the selling points.)