Finally getting around to moving the Ultegra groupset off my RT-58 and onto the Roubaix. Aside from changing the chainset, the only other part which may need changing is the front derailleur. The RT-58 is a band on Ultegra item, whereas the Roubaix frame has a braze on mount, so I cannot simply swap it over. Does anyone know of the Sora FD will work OK with Ultegra 6800 shifters? The Shimano compatibility charts don't suggest any form of interchangeability, and I have read that the 6800 uses a slightly different pull ratio???