I am 6'8" and currently ride a 63.5, but.... besides the 64 I haven't found anything larger. This kind of brings me to the question of why Giant doesn't make "giant" frames? Anyways I am very limited to what I can ride. I have Trek 7. 2 FX, fairly new to cycling (2 tlr years) and have made my bike to fit me. I put drop bars on with 120mm stem and the bike feels very comfortable. Night and day difference to what it was before.