Running 105 everything on my roadie, and it has developed an annoying habit of the chain slipping over the cassette. It's not the indexing etc as the chain stays on the same sprocket, but seems to ride up the teeth then slip over a few teeth before settling down again. Happens maybe once every 20 pedal strokes
Tried changing the chain, cassette, front chain rings and the rear mech to no avail- any ideas!? Am I missing something really obvious (distinct possibility)?