I have a Campy 11-speed setup with Record derailleurs, a 50/34 Chorus crank and 12/29 Chorus cassette. I've been to two bike shops to adjust the front derailleur but when I get on the road I still have problems dropping the chain when shifting from the small chainring to the large. The chain will move beyond the large chainring and drop out. On the stand, if I adjust the limit screw, I can correct the problem. If I move the limit screw too far inwards it won't move the chain to the large chainring and if too far out, the chain will drop out. An 1/8 of a turn each way will affect the movement and will work differently if on the large or small sprocket. I don't believe the position of the limit screw should be that critical and although it will work on the stand, when I ride the problem will resurface. Is there an inherent problem with this setup or is there something both bike shops and myself are missing?