Originally Posted by
DVC45
The Synapse has longer top tube compared to its seat tube. It'll fit just fine.
True if you are comparing it with a standard 51cm frame with a horizontal top tube, but the Synapse's rising top tube and more upright position makes the comparisons more complex.
Yes the bike would normally fit more like a 53cm, except that the Synapse's geometry is actually slightly different from Cannondale’s standard road bike set-up. It has a bit of extra height in the head-tube and a shorter top-tube which results in a more upright position.
A longer stem and/or setback seat post can stretch out the cockpit though, so as long as you are comfortable with the more upright position you should be very happy.