Originally Posted by shelbyfv

If the only difference was frame material, I'd probably choose alloy 105 over carbon Tiagra. However... the Synapse has a few features that might impact long term satisfaction. First, it will fit much wider tires, up to 35mm. Second, it has a normal BB, vs the press fit BB30 of the CAAD13. Also, it has gearing more appropriate for most riders. Along those lines, if you live in a hilly area, the Topstone 1 with some 35 or 38 slicks would be a versatile option.