Ultegra 6870 di2 dropping chain

[raggi]

Hi,

Recently I've been having a problem with my di2 setup where if I'm in the big ring (52/36) and one of the easiest gears in the back (11-28 cassette), when I then shift to a harder gear in the back, the chain seems to end up in this weird limbo between the front chainrings, where it's hopping up and down and it won't stop until I shift again at the front..

It feels to me like it has something to do with the automatic trim of the FD but I'm not well versed enough to pinpoint the issue.

I'm using Quarq DZero cranks with old(ish) Specialized chainrings.

Anyone had this happen and/or knows of a potential solution?

[havana]

I had a similar problem. Read the manual and adjust the auto trim function.

[raggi]

Tried fiddling with adjusting the trim and I'm fairly certain it's spot on now, I am however, still having the same problem.

The same thing has also started to happen sometimes when I hit a particularly rough & bumpy patch of road.. Could it be something to do with either the angle of the FD, or that the chainrings are bent/worn out?

[nycebo]

Could it be something to do with either the angle of the FD, or that the chainrings are bent/worn out?

If you haven't tried to straighten your RD hanger, I suggest that be the first place you start.

[kode54]

Tried fiddling with adjusting the trim and I'm fairly certain it's spot on now, I am however, still having the same problem.

The same thing has also started to happen sometimes when I hit a particularly rough & bumpy patch of road.. Could it be something to do with either the angle of the FD, or that the chainrings are bent/worn out?

if it jumps off while hitting bump...could be that the chain is too long and not enough tension. i've had that happen once when i shifted going into a turn, while hitting bump.