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I would wonder how they go about purging old air, risk of damageing a tube I'd think.


Just guessing, but could turn the wheel so the valve's at the bottom, release all the pressure and fill up on nitrogen, let it settle a minute, then let about 1/3 the pressure out again. Since nitrogen's lighter than air all the nitrogen'd be at the top of the tyre and would force the oxygen out. Then just top up on nitrogen.

Matt Electronic mods for TBA/SM!