"I've got a Shimano Ultegra front derailleur & a compact 50/34 chainring, and whenever I'm in the big ring/small cog combination the outside of the chain is rubbing against the inside of the front derailleur cage.
I've been hesitant to do any tweaking myself, as A) I have no wrenching experience beyond washing & lubing; and B) Lennard Zinn's book is a bit oblique about addressing this specific topic. But then yesterday's mail brings me ""Bicycling Magazine's Bike Tune-Up Guide"", and right there on page 15 is what seems like a clear, concise explanation of how to fix my particular problem:
""Shift into the largest cog and smallest chainring combination. Look between the inside of the front derailleur cage and the chain. There should be 2mm of space. If not, turn the inner limit screw (usually the closest to the frame) until you get that 2mm of clearance. Next, shift to the smallest cog, biggest chainring combination. The outside of the cage should clear the chain by 2mm. Adjust the outer limit screw, if needed.""
Ahem. Yeah, so, well, I try this and...nothing. Cage doesn't move at all. I try tighter, I try looser, nothing, nada, zip, zilch. I figger maybe I'm turning the wrong screw, so I try the inner limit screw. Nope. (Plus -- separate problem, I guess -- now I can't get the inner limit screw back in!)
Help! Any ideas what I need to do to get the front derailleur cage to not rub against the outside of the chain when I'm in the big chainring/small cog combination?
Thanks."