I usually ride a 54 cm frame, but I've had a 56 fit great and a 52 fit ok. For the longest time, I only rode 52 cm frames because that's what I'd been told fit, but I've started feeling more comfortable on larger frames. Actually, I just finished a 54cm Schwinn Peloton and ended up setting it up with a higher seatpost and more aggressive fit than any of my other bikes, it naturally feels more comfortable that way. I do wish I had learned I had a range of sizes before, I've passed on so many cheap or almost free bikes because I thought they would never possibly fit.