Well said!!!I work at a tire store as an alignment tech, have for 30+ years. This is a running joke for us! Like a couple of you guys said, "regular" air is already 78% nitrogen so damn the difference! That being said a lot of people insist on it! I have access to it and can get all of it I want for free. Guess what I have in all my tires? I'll give you a hint, It ain't nitrogen! Nascar teams that are trying to control their tire pressures to within 1/4 of a pound are the only reason that I can see for it, but to each his own!