Original post by: stephenafischer ,
I have been having a similar problem of ghost shifting on my full suspension mountain bike. This first started after breaking my chain on a ride. When I replaced the chain, I also decided to replace my rear derailleur cables and their sleeves. After noticing the symptoms I ended up replacing the rear cassette based on advice from a bike shop. Following that with no luck, it became very frustrating and I started to think about the exact circumstances when it would ghost shift: - Only when on the bike, and not while on the tuning stand. - Only after putting a big load on the peddles or when going over a big bump. Then it dawned on me that perhaps it was connected the movement of the rear suspension on the bike. I then looked at the derailleur cable sleeve that runs underneath the bike and noticed that when I was standing on the bike, the sleeve which normally has some slack, gets tight against the frame due to the travel of the rear suspension while weighted. I then replaced the cable sleeve with a new segment with an additional 1" of length. After this, the sleeve no longer pinches against the frame, and the ghost shifting problem has gone away!