Well it's 80 revolutions of the chainring so two strokes per revolution and gear inches is the equivalent of a certain wheel diameter- not the same as development.
Try playing with this:
http://home.earthlink.net/~mike.sherman/shift.html
at the bottom for a particular gear combo it will give you the speed at a picked cadence so at 80 rpm you need to go 3.8 mph to get to the top in 2 hours
a 22/36 combo will give you 3.9 mph at 80 rpm. 16 gear inches.