philbob57

Computing stack and reach from a frame requires a lot more math than most bike sellers know.

I used to be 5' 7", and Competitive Cyclist recommends a 22" TT for me, so my legs are probably a little shorter than average. I know I feel cramped on a square 21" frame. I felt way too cramped on a 50 CM Gitane Gran Sport, but that was with C-T measurement. The 51 CM Olmo, measured C-C, is likely to be within the range that you'd like..

BITD, I think people followed the probably most common recommendation of 1"-2" between crotch and top tube. Then they actually took test rides and picked the bike that appealed most to them according to their own value system. Another common reco was (cycling) inseam minus 9"-10". For many people, the 2 recos same out the same. IOW, most cyclists didn't bother with the actual TT measurement, but TT came into how the bike felt on the test ride. I know I rejected San Rensho, Bassi, Rossin, and other Japanese bikes but liked British and French bikes. If memory serves, the standard Japanese and Italian bikes were square the last time I bought a bike (1981), and the Brits and French had longer TTs on their 54s (again, measured C-T).

If you measured yourself accurately, you can probably be comfortable and efficient on any diamond frame between 52 CM- 56 CM C-T (50-54 CM C-C), unless your proportions are much different from average. I agree that ST and TT are the most critical measurements. You can do a LOT of adjusting with stem, bars, and seatpost.

BTW, different materials and different builders produce frames that ride differently. Even if there were a single set of measurements that is best for you, and if you rode a dozen bikes with those measurements, you'd probably love some bikes and not others. IOW, obsessing over measurements is far from a sure way of finding a bike you like. At some point, you have to make a choice and hope for the best.