tire pressure

[flynrider]

Ausieflyer,

I read that on another site last year. Tongue in cheek the poster then said that over time as the O2 leaked out, and you refilled the tire with more air, over time you would have all N2 for free!! and that was his story and he was sticking too it

That's always been my theory. You start with 78% nitrogen. Next time you top off the tire (to replace the oxygen that permeated through the rubber) you end up with 85% nitrogen and so on. After topping off the tire a few times, you should be pretty close to 100%.