Originally Posted by
fusilierdan
I guess the question could be is the standover number of 30.86" the actual height of the top tube or the longest inseam measurement suggested for that model.
It's the actual height (or very close) to the top of the top tube, at the center of the measurement between the seat tube and head tube junction. The top tube is sloping, so it's lower as it gets closer to the seat tube and higher as it gets closer to the head tube. Keep in mind, tire size will make a difference, too.
The 50 is the correct size IMO, the 47 is too small and the 53 too large.