Originally Posted by
TerryDi2C
I also sent this via email, but thought I might as well reply to the thread as well ;-).
Sometimes a Di2 rear derailleur is just off by 2-3 gears. It doesn't happen often, but it does happen. There is no real way to fix this. You cannot use E-Tube Project 3.4.5 / 4.0.4 / 5 or the SM-PCE1 / SM-PCE02 to fix this.
I don't know whether or not this is possible with E-Tube Project OEM, but since no one other than factories has access to that it doesn't really matter
.
Shimano's method to fix derailleurs that are off by 2+ is to replace them. Usually they'll also replace them if it's out of warranty.
A derailleur hanger or frame that are slightly out of spec (too thick or too thin) is also a possibility... but you would then end up with a derailleur offset one gear at most. Two seems a bit excessive.
Since a bike shop has already looked at the issue it's pretty safe to say that the hanger is straight and that the derailleur is installed correctly. They should've called Shimano though, and I think that is the next step to take ;-)
Hi All,
I stumbled on this thread after having a similar issue recently.
I am on 11 speed Ultegra Di2. On my ride this weekend I realised that I couldn't access the two BIGGEST cogs on my cassette.
My head unit indicated that I was in the biggest cog, but the derailleur (RD-8050) was in the third biggest.
The e-tube app also thought the RD was on the biggest cog.
The system was also trying to change down beyond the smallest cog.
I took it to the LBS; and they had Shimano remote connect to the bike to investigate.
Shimano are none the wiser for why the fault occurred; but the fix was to replace the rear derailleur.
Very strange fault. The broken derailleur had down about 17,000km since new. Not exceptional, but nothing to complain about either. I'm just happy to have it be up and running again.
LBS also found you, Terry on Instagram I believe - thanks very much for your help. It was this post, and this reply which made me realise I couldn't fix this at home and needed to get to the LBS so that they could work with Shimano.
Cheers
Mike