Usually we can fit a range of frames. I have a 32.5" inseam and 54-56 works well for me. Ideal is 54-55 w/55 TT. However, I have a 58 Masi road bike that I can ride pretty well. The problem is that in comparison to a 54-55, the 58 just doesn't feel "right." If it were me I'd get the proper size in an endurance bike as suggested by genejockey. My current ride is a CAAD 12 so I'd go to a Synapse. FWIW don't rely on Cannondale stated sizing. My CAAD 12 is badged a 52 but when measured using a virtual TT it is actually a 54.