In response to the question about whether you can put nitrogen or helium in tires in the now closed thread (I read through this one and didn't see it addressed):
Yes, you can put nitrogen and helium in them. Helium won't last long-- it diffuses pretty quickly through both latex and butyl, and you'll find yourself refilling throughout the day. Nitrogen is fine. The air you put in them with a tire pump is 78% nitrogen already. I use nitrogen at carson because I'm lazy and don't like to deal with pumping to high pressures-- I keep a nitrogen cylinder with a regulator and fill hose in my locker there. Carbon dioxide will also work, but leaks out much faster through butyl rubber, so it's fine in the little emergency fill cartridges, nitrogen is preferable and comparably cheap.