I'm 5'7" and have a variety of bikes ranging from 48cm to 56cm and they all fit. You really need to try the bike first to make sure it's correct for you. My 48mc required a slightly longer stem and a layback seatpost to give me a perfect fit and is now possibly one of the comfiest bikes I have size wise. The 56cm is an old school steel frame and is also a perfect fit. Too many variations to consider with modern bikes nowadays to buy untried for me