Depends on alot of things. I am 5' 10" and have a Marin 18.5" frame which is too big for me. I don't have any standover clearance. The top tube length feels good though. I am getting a new 17" frame with sloping top tube and it also has same length top tube. Best advice is to go to a bike shop and try out a few 16" bikes. More importantly though is the top tube length because of the design these days. I asked this question before and it is horses for courses, so many factors to take into account. Try some of the fit calculators to see what ball park top tube you would need.