On Tuesday, October 2, 2018 at 11:10:59 AM UTC-7, jbeattie wrote:
O.K., reality check. I was riding in with my son this morning, and he had a sudden attack of ghost shifting or skipping of some sort. I was watching his rear wheel (my usual position, hunkered down behind him), and I didn't see chain skip.

IME, ghost shifting usually happens with a sticky cable at the BB, but what is the likelihood that this is a casette/chain issue? I changed the chain but not the cassette a month ago. It worked beautifully -- no skipping, but I'm wondering if you can hit a tipping point where the cassette goes and the chain is O.K., and you get shift issues. If the cassette is too worn, I usually get problems the moment I put on a new chain and not later.

-- Jay Beattie.

This isn't uncommon with Campy gear. You have to have, A. Perfect alignment of the rear derailleur on the cassette and B. The shifting ratchet cannot be overly worn.

The Japanese stuff usually doesn't have this problem. I don't remember pulling these things apart but while they are somewhat sensitive to misalignment I haven't seen a worn ratchet causing problems.

The rear derailleur has such spring pressure that I can't see sufficient drag from the bottom bracket wire guide causing any troubles.