I'm a happy campy user, until this week. I "upgraded" my 2006 centaur levers with chorus '06 levers. never had any problems with the centaur, love them. but on 3 rides since sunday, 1-2 times per ride, the left paddle doesn't engage the ratchet mechanism, and therefore I cannot shift to the big ring.

not sure how i fix it, I just keep playing with the levers and eventually it works again. wouldn't be a huge problem, but this saturday is by far my most important race of the season and simply cannot have this happen in race situation.

obvious fix is to put my left centaur lever back on, but that's not the elegant solution, and wtf, almost $300 for this?

Any ideas what's causing this, what could fix it?