I agree with gyeswho, as the vintage cannondale track frame is the stiffest ever measured by someone (there is a chart, but I don't know where to look). I had one and it was a beast for riding long distances. NO flex= great for track, as that is what it was designed for, to quote bikesnob "laterally stiff but vertically compliant" is good for long rides. When I took my CAAD5 to the bmx track, it was great. I then rode some cruisers there and was amazed how much the bike rattled me. There is a reason that bikes are made stiff. Comfort isn't one of them.