Rear derailleur shifting causes chain drop

Bobblehatboy
Bobblehatboy Posts: 10
edited July 2019 in Workshop
Hello

At random times and when I'm not putting any pressure on the pedals, I shift into a smaller cog and my chain drops off the front large ring.

I have Sram Red groupset.

Any ideas what's going on?

Thanks

Comments

  • darkhairedlord
    darkhairedlord Posts: 7,180
    Chain too long, FD limits not set, spring in RD worn out, slack in BB. Need to pedal a bit harder when changing gear.
  • photonic69
    photonic69 Posts: 2,674
    Drops which way? Out to pedals? In to smaller chainring?


    Sometimes. Maybe. Possibly.

  • Bobblehatboy
    Bobblehatboy Posts: 10
    PhotoNic69 wrote:
    Drops which way? Out to pedals? In to smaller chainring?

    Into smaller ring
  • me-109
    me-109 Posts: 1,915
    Sounds like the outer clearance on the FD is too tight so when you shift to the outermost cassette sprockets (9, 10, 11) the outer plate makes contact and chainline forces the shift.
  • photonic69
    photonic69 Posts: 2,674
    Possible that your FD cage is not parallel to the chainring and pointing inwards to the rear?


    Sometimes. Maybe. Possibly.

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