An old cycling teammate of mine always drills out his MTB rims to accept Schaeder valves, but then he runs presta tubes with the adapter. This is not the filler adapter, this is sort of a grommet that fits in the Schraeder hole and shims it down to presta-sized. That way if he gets caught with a flat and no tube, so long as he can find someone to bum a spare off of, it doesn't matter which they're riding. I carry a pair of the adapters in my MTB tool kit in case I find another rider stranded with a flay who has Schraeder rims.

The gas station air hose only works when used on a valve with a spring-loaded central needle, like a Schaeder. The screw-on Shraeder filler adapter is hollow so there's no needle, nothing to depress the button in the air chuck, which is what turns on the air flow.