I live in Portland. Hills if I want them, as well as many flat routes. I just switched from 46x16 to 48x16 to finally 48x19. Big difference!! Took about a week to get the hang of it. Way easier now to mash away from stops and up hills. 48x16 was fast as hell for me (on the flats), not to mention the strain on my knees (starting and stopping). 48x19 now makes hills seem flat. Spin, Spin, Spin. Only thing is out of saddle mashing feels a bit unproductive? My G.F. runs 46x20 and she keeps up with me??? (more hills on her commute). Anyways spinning is better for you knees and in no time you will have thighs like this guy http://www.youtube.com/watch?v=R-fqo...eature=related