Quote Originally Posted by Catriona View Post
They put larger seat angles on smaller bikes to shorten the top tube & reach for smaller riders...
This answer wnyrider's wonder. The seat tube angle of my Fuji Finest RC XS is 76 degree. I'm all right with that.

And the design of tiathlon bike is different from road bike. Check this link.

Cervelo uses different approach to shorten the top tube length for small riders: reduces the head tune angle.