Originally Posted by
kjunx
Look at your Standover height (on their website) to get a feel for what is best for you then go check out a few similar bikes at your LBS. This helped me get a feel for what the 56cm would be like even though i didn't ride it.
TT length is the only measurement that matters. Standover height is generally useless, albeit, it's not taller than your inseam.