I have been having a lot of trouble setting up the front derailleur on my new road bike build. I have only worked on one other road bike before, but that one I got working faultlessly even though many of the components on it are old and somewhat used. I am used to working on mechanical things, but bicycles are a new venture for me so I need help from experienced people and/or professionals, please!
My FD problems: I am having serious problems with chain clearance AND chain dropping from the front gears. I have spent a lot of time adjusting the FD and trying all kinds of positions and limit screw adjustments.
It seems no matter what i do, I either get bad chain rub on the FD cage, or I get the chain dropping from either the small or the large chainring.
I have a full Campagnolo Veloce (2013) groupset on my steel Coppi, 34/50 compact crankset and very short chain stays, which makes for quite big chain angles.
Here are my questions:
1. Campy FD is supposed to go from small to big in three clicks. That would leave one more click to adjust trim while on the big ring. Is this correct? How should I then adjust the high limit screw? If I adjust it so that it allows for the fourth click (thus trimming on the big ring), the chain will sometimes overshift out of the big ring if I pull the left trigger too far. Then if I set the limit screw to only cover for the three clicks, then there is no trim capability on the big ring. What to do? I almost don't need the trim function on the big ring, the chain only lightly rubs on the FD cage's resin insert while riding on big/small, the highest gear.
2. The chain will jump off the small chainring quite often. I have set the low limit screw as close as possible. The chain even sometimes overshifts the small ring when the low limit is set so that the chain is rubbing against the FD cage on small/big (the smallest gear). Maybe it's a question of FD cage angle? Cable tension doesn't help, if I tighten the cable enough to stop chain from jumping over the small ring, then the biggest rear cog becomes unusable because of chain rub on FD cage... What should I do?
3. What about chain tension? Campy instructions told me to cut the chain so, that when riding on small/small, there's a 15 mm gap between the chain and the RD body. Trouble is, with this chain length, there's almost no tension on the RD spring when running on small/small. Of course small/small isn't used when riding, but I would imagine there needs to be some chain tension even on small/small?
4. How about the FD high limit screw - should I adjust the clearance in relation to the cage outer plate or in relation to the small resin insert on the FD cage? If I adjust the chain to clear the resin insert, there's quite a gap between the cage outer plate and the chain. Or should I move the FD higher up, so that the chain wouldn't normally touch the resin insert first?
I am very puzzled, and seriously need help. I'm hoping someone will be able to help me - please tell me exactly how the Campy FD is supposed to operate (the manual isn't worth a damn) and how could I fix this problem. Thank you!