I'm 5'6" and I should be riding a 54cm frame, but I have super short torso (like the top of my head cannot be seen from the back of my car - I look like a little kid driving). Anyhoo... I have a 50cm Bianchi eros donna and it is the first bike in my entire life that has fit me well! It is SO much fun riding a bike that feels like an extension of my body!