Originally Posted by
groovestew
Mine is 46 / 17 * 27 = 73, so a bit smaller (but a noticeably smaller chainring and slightly smaller cog. Math!). I wouldn't go any bigger because of some of the hills on my commute (which exceed 10% grade for a few short sections), and in fact, I have a 44T chainring waiting in my parts bin. Not there yet. Not quite.
I spent a winter commuting on a fixie with a 66" gear. That really taught me to spin fast. I clocked myself at an estimated 180 rpm. It's good to be able to spin without bouncing on the saddle.
I have a track racing bike with a front brake and an 83" gear. I don't think I could climb a 10% grade on that. In fact, I don't think I could climb it with my 73" gear.