I am crew for a Midget race car and we use nitrogen because the tire
pressures increase less when hot than putting "air" into them. Its a
standard practice for hard core asphalt racing teams and does work. We
don't care about long term degredation of the tires and it makes a couple
of pounds difference in the pressures after a main event.
My .02
Daryl of AA Transaxle
Duvall, WA. (Seattle area)
(425) 788-4070
1-877-377-0773 (toll free)
aatransaxle.com (web site)