Chain slipping of jockey wheel

noccy Posts: 2
edited August 2015 in Workshop

I have a Cervelo S3 with Shimano Ultegra rear derailleur. The bike is quite new, and has only been used for about 500 km.

Now, the chain has started to slip of the lower jockey wheel on the rear derailleur, and running between the wheel and the cage. Have a look at this video to see what happens:

Could this be an adjustment issue, or is it more likely that the cage is damaged? Neither the chain or the jockey wheel has any sign of wear.

Some photos:



  • desweller
    desweller Posts: 5,175
    Loose jockey wheel screw?
    - - - - - - - - - -
    On Strava.{/url}
  • lpretro1
    lpretro1 Posts: 237
    Bit hard to see from video but is the gear hanger bent - if so that will be why the chain is coming off the jockey wheel as the mech is pushing against it
  • laurentian
    laurentian Posts: 2,474
    The photos, especially the last one, seem to show that the bottom jockey wheel is way out of alignment - I would guess either not set/tightened correctly or bent hanger as mentioned above.
    Wilier Izoard XP
  • keef66
    keef66 Posts: 13,123
    I get the impression from the last photo that the rear mech cage itself is bent / twisted. The lower jockey wheel seems to be pointing in a completely different direction from the upper. Has it been dropped or has somebody else ridden in to you?

    You should also get the alignment of the mech hanger checked.