I was actually looking at either rollers or a trainer - each have their advantages and disadvantages. One question I have about trainers (specifically the Kurt Kinetic variety, but this isn't necessarily brand-specific): do I have to worry about physical stress on the bike frame while using one? It seems any rocking motion in the bike will cause excess flexing of the back end of the bike. My bike is CF, so... just curious if I need to worry about damaging my frame from using a trainer...