My wife's bike (spec below) seems to drop the chain from the front for no apparent reason. It falls inwards towards the BB shell, not out. It can do it from the middle ring at the front or the small. Sometimes when shifting but others not*
I've looked at indexing and chain length but that's all I can think of. The chain rings are a little worn (not too bad) and the chain and cassette are new >50km.
853 Inbred 14"
Raceface Evolve cranks
9 speed Simano road casette
XTR rapidfire shifters
Thanks a lot,
*apparently. Not that I don't believe my wife, I just can't get it to do it for me.