Campy floating chain: worn chainring?

[keevon]

I've got a 10 speed Record crankset that's recently developed a problem. When downshifting from the big ring the chain occasionally won't engage the small ring, but rather 'float' on top of the teeth for a few revolutions before it engages. This causes my cranks to spin freely, which is a bad thing starting up a hill. I've tried the downshift both under load and while soft pedaling, both of which have caused the floating problem. The chain is not new, but is still acceptable in terms of wear (less than 1/16" elongation over 24 links).

Could my chainrings be worn out? I purchased the crankset used a few years ago and have since put several thousand miles on it, but the teeth don't appear to have the typical 'shark fin' profile of a badly worn chainring. Things run smoothly when the chain is engaged with the rings. My other bike with a Record crankset and a similarly worn chain doesn't have this problem, though I suspect the rings are newer.

Thoughts?

[haimtoeg]

When you shift from the big ring to the small ring you create chain slack that has to be taken up by the rear derailleur. If it is dirty, not lubricated, poorly adjusted or whatever else, it will not be collecting the slack as rapidly as you want. I'd start looking at that.

[regularguy412]

Actually, I had this 'floating' problem when my chain was worn. The worn chain even caused some chainsuck on a couple of occasions, although the 'float' for me usually occurred going from small ring to large ring. It would ride on the big ring for a turn or two before dropping into place.

Check your chain for 'stretch' and also for side-play. My chain wasn't beyond the stretch maximum, but the side-play was the apparent culprit. I put on a new chain and the problem evaporated.

Caveat: I'm on Shimano, so you might be advised to take this with a grain of salt. However, that was my experience.

Mike in AR:beer: