http://www.sheldonbrown.com/gears/
Using the calculator for nominal 26inch wheel, 175mm cranks, and 32/16, the gain ratio comes out at 3.8 (and the gear inches comes out at 52.0)
Using the calculator based around 700x50 / 50-622 / 29inch tyre, 175mm cranks and 34/19, that gain ratio also comes out at 3.8 (and the gear inches calculates to 51.8)


















