Originally Posted by
McBTC
...looks like supersix in size 54 cm comes with a setback seatpost. On a larger frame you can have a straight post if reach is an issue but still get the knees behind the pedal spindle as a result of a more relaxed seat tube angle.
That's true on larger bikes that have actual relaxed seat tube angles, but even the 56 Supersix still has a seat tube angle that is steeper than the 73° median. With "normal" set back, you aren't going to be able to go to a zero post until the seat tube angle is less than 72°.