I ride an older 56 cm bike, it is a tad tall, and a tad long for me. I got oout the tape measure, and measured ever thing on my old frame. Was out the other day looking at new frames, put the tape on a couple of new high tech carbon frames. The carbons all seem to be very long in the top tube.

A little work with a tape measure, paper, and pencil. Will be a good investment when shopping.