Have been having a problem now for awhile which no one seems to be able to fix. Periodically when I am riding in the big ring, especially up hill under some load, and switch to the small ring, the chain fails to engage the small ring. Suddenly no power at all which isn't good. It looks from the riders perspective like the chain is lined up correctly, not too far L or R, but just doesn't engage the teeth on the small ring. The bike is a Look 585 with Campy Record gear, 50/34 compact front. 8 years old. One bike shop told me it was a derailleur problem, replaced the front derailleur, and put on a new chain, made the problem better but not completely fixed. Second shop said they called campy, think it might have something to do with the crankset not being completely lined up correctly because of being taken apart and put back together. This has only been done at most 2-3 times to replace the bottom bracket. They don't seem to think they can fix it that the crankset needs to be replaced. Really? After 8 years, probably 40-45 K miles. I am 5'7" weight about 145 so I don't think I put a lot of stress on it. Oh and chain rings themselves are not 8 years old, more like 2, have maybe 7k miles at most. Second shop took 3 links out of the chain, said it was too long but that didn't fix it. Any thoughts?