It should be noted that bike frame sizing has dramatically changed in recent years. It used to be a frame size was (and still is) measured from the bottom bracket center. What has changed is most modern road bikes have a virtual measurement for the frame size, not the actual seat tube length. People are now riding with significantly more seat post out of the frame now. If you look at old (lets say 1938) road bike racer footage on you tube, most racers had 0ne, two maybe three inches of seat post out of the frame. Now there is the "compact' frame", with the slanted top tube. Now it is common to have 9-10 inches of seat/ post out of the frame. I am an old school roadie (40 plus years) I am 5'-6" short. I used to ride 52cm frames (seat tube length) Fast forward forty years, and now I will not consider riding a frame with more than a 44 cm seat tube.