I'll jump in here with another stupid beginner question about frame sizing. I understand C-C, and how it impacts the reach and orientation to the bars - very well. But how useful is the C-T measurement, when the end of the seat tube and how far it extends above the top tube varies so much among manufacturers? I mean, that measurement probably varies 5cm or more, and it doesn't seem to directly affect anything other than how much exposed seat post you end up with?

KeS