I don't know about that. I'm 6' and compared to the golden ratio I'm pretty proportionate (yes I've checked lol). I ride a 53 and I'm very comfortable on it. Even thinking about getting a slightly shorter stem. Though if I did it again I probably would go with a 55 and adjust the saddle/stem/bars accordingly, just so I could have less toe overlap. (with my current pedal setup I don't have overlap anyway, but its close)