I prefer my rides a little snug. I can fit a 56cm, 57cm very well. I just picked up a 54cm and know from feel that 54cm is nice and fun I am 5'9" with a 30" inseam. I feel that with me at least the smaller the better i can get a feel for the bike as opposed to the bike riding me. If that makes sense. Haha anyways i enjoy a tad smaller than 56,57.