Actually, you know what, I just looked at this calculator and a 50-24 with 12-14-16-18-21-24-28-32-36 didn't seem to have much overgap. Is this possible to do? Where would I find such parts? For 167.5mm? And what other parts would be needed to make it fit a Marin Mount Vision Pro, 2008, 15.5" frame?

http://home.earthlink.net/~mike.sherman/shift.html

http://www.bikepedia.com/quickbike/B...unt+Vision+Pro