Quote:
Originally Posted by BobRederick
Nitrogen has a greater thermal conductivity than air, so if the heated nitrogen can get to a cool surface (the wheel rim?) the heat can be carried off more quickly resulting in a lower temperature. How much lower? I can't answer that.
|
But Bob, plain old air is 80% nitrogen. And of the remaining 20%, most is oxygen, which has nearly the same conductivity as nitrogen. So how much different can the overall conductivity be?
Nitrogen has one important property - it slides money out of your wallet, and makes you feel good about it. Plain old air can't match this.
By the way, the Car Talk boys agree. As do 144,000 Google hits for "nitrogen tires scam". See, for example,
http://www.cartalk.com/content/colum...tember/05.html
Any good air compressor will remove moisture from the compressed air, which is the only possible argument. If you use a cheapie air compressor (the kind you put quarters into at the local convenience store), and you live in a humid environment, then you may put a bit of moisture into the wheel, and in 100 years the wheel may rust a bit. Other than that - nada.
It is sometimes claimed that nitrogen diffuses through the tire's sidewall more slowly than "air", and so with 100% nitrogen (from your tire guy's tank), the tire pressure doesn't drop as fast as with 80% nitrogen (plain air). Makes sense? Nope. The oxygen molecule is bigger than the nitrogen molecule, so it is slower (not faster) to pass through microscopic pores.
Save your money. Buy swampland in Florida. It has a bigger chance of paying off.
Bill