Shifting di2

Discuss light weight issues concerning road bikes & parts.
Timmy269
Posts: 205
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

I have for several years di2 6870. The latest months the rear derailleur shifts by itself. He is adjusted how it should be. He shifts on my bike stands from the 28 cog to the 25 cog, it's not that the problem is on the adjustment because I can see on my Garmin he shift from cog 1 to 2. On a ride he does that also from the 6cog to the 5. What could be the problem?

by Weenie


2old4this
Posts: 366
Joined: Mon Jan 13, 2014 7:26 am

by 2old4this

I'd check the low limit screw for the first issue (shifting from 1 to 2.) For "auto shifting" from 6 to 5, it may be an alignment issue. Overall, it sounds like you have to re-setup your rear derailleur...

Timmy269
Posts: 205
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

I have re alignment the rear derailleur a couple of times but it won't help the problem. I checked the Low limit screw also en turned that the derailleur can go a little more to the spokes but that didn't help.
I noticed on the garmin that there is a shift, I can see on it that the gear goes from 1 to 2 and also form 6 to 5. I think if the shifting is of a bad setup, the shift is actual vissible on the garmin.

I looked on the web and there are a lot of problems with di2 ghost shifting

XCProMD
Posts: 800
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

Usually the kind of ghost shifting you report in Di2 is related to problems at the encoder. The encoder is the part of the servo unit that reads its position and sends feedback to the CPU (the “brain” of the system)

I have also come across a some cases with the same symptoms as yours in which the problem was the current meter giving false readouts. That makes the system shift to avoid an overload and in case of a persisting high read out, to shut down the derailleur.

If the problem is the encoder the only solution is to buy another RD. We have repaired some RD’s for fun but is always unreliable, specially towards moisture.

If the problem is a wrong current readout you can try changing battery. Sometimes a bad battery gives fast current spikes that make it to the RD.

Di2 works fine but can be a bitch to live with.


Timmy269
Posts: 205
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

XCProMD wrote:
Mon Jul 09, 2018 10:33 am
Usually the kind of ghost shifting you report in Di2 is related to problems at the encoder. The encoder is the part of the servo unit that reads its position and sends feedback to the CPU (the “brain” of the system)

I have also come across a some cases with the same symptoms as yours in which the problem was the current meter giving false readouts. That makes the system shift to avoid an overload and in case of a persisting high read out, to shut down the derailleur.

If the problem is the encoder the only solution is to buy another RD. We have repaired some RD’s for fun but is always unreliable, specially towards moisture.

If the problem is a wrong current readout you can try changing battery. Sometimes a bad battery gives fast current spikes that make it to the RD.

Di2 works fine but can be a bitch to live with.
Thanks, how can I decied it is the encoder or a wrong readout?

XCProMD
Posts: 800
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

Take your bike to a Shimano dealer that has a PCE interface so they can diagnose your system. Most likely they will tell you everything is fine but it’s worth the try.

Shouldn’t they find anything wrong try with another battery from a system that is working correctly and check if if solves the problem.

Check also every connection, make sure that everything is properly plug together, ie no loose connections.

If none of the above helps then most likely you have a nice toast RD. We used to have a bucket full of them.

Timmy269
Posts: 205
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

I will go to the lbs and see what the diagnostics is.
In that bucket of you in the shop, where that all dérailleurs with faulty software?

XCProMD
Posts: 800
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

Hardware in all cases. Software is fixable.

Timmy269
Posts: 205
Joined: Tue Nov 25, 2014 2:34 pm

by Timmy269

Today I went to the lbs and the firmaware was already up to date and the systom didn't give any fault caudes.

He called Shimano, and they never heard of this problem before. They suggested to change the shiftlevers and see if that helps, so not change the rear derailleur. :-(

XCProMD
Posts: 800
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

Can’t they lend you a battery from another bike that shifts properly?


Inviato dal mio iPhone utilizzando Tapatalk

User avatar
Calnago
Posts: 8526
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

Whenever I see threads like this, or in real life, my first instinct is to say... “just turn the adjuster a quarter turn to tighten/loosen the cable”. It’s usually not received very well. Point being... don’t always trust your instinct.
Seriously though, this is probably the main issue I have with electric systems. They work, when they work. But when they don’t, it can be extremely frustrating.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

XCProMD
Posts: 800
Joined: Sat Jan 26, 2008 10:25 am
Location: Cantabria

by XCProMD

It’s mainly Di2. e-Tap seems to be more robust, apart from the battery tabs and some bugs in the first batches, and EPS is plain bombproof, other than the occasional dead V1 battery.

Skickad från min iPhone med Tapatalk

SilentDrone
Posts: 200
Joined: Fri Sep 22, 2017 5:55 pm

by SilentDrone

Calnago wrote:Whenever I see threads like this, or in real life, my first instinct is to say... “just turn the adjuster a quarter turn to tighten/loosen the cable”. It’s usually not received very well. Point being... don’t always trust your instinct.
Seriously though, this is probably the main issue I have with electric systems. They work, when they work. But when they don’t, it can be extremely frustrating.
I’ve read so many comments on here saying that Di2 is preferable to mechanical precisely because you can set it and forget it, no mechanical skill or maintenance is required.... #notexactlycorrect


Sent from my iPhone using Tapatalk

User avatar
Calnago
Posts: 8526
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

If someone has zero mechanical skill, or just no desire to ever want to touch a screwdriver, then I’d say go electric and try to remember to plug it in every now and then. I say that because if they have zero aptitude or desire for working on their bikes, then they’re going to be relying on someone else regardless of whether it’s electric or mechanical. And electric, once set up right, really is kind of a set it and forget it thing. You push a button or two, and it does a thing or two. The same way, every time. That’s fine. But it’s soulless. I love shifting a well tuned mechanical system and that feeling is reinforced every time i get back on one after spending time on an electric group. It’s just fun to me. And I like knowing, because I actually do possess a fairly decent level of mechanical skills, that there isn’t much that could ever go wrong that I couldn’t fix in very short order. I can’t say that about the electric stuff when it fails. I’m as puzzled when pushing the button doesn’t do anything as anyone else. Then the trial and error troubleshooting begins. It may be quick, it may arduously painful. But I know with mechanical, if something doesn’t work I can generally diagnose why in about a minute max. And then fix it in not too much longer. But it’s pretty much a set it and forget it system as well, requiring only proper cleaning and lubrication. To each his own, as long as there’s choice I’m happy. But I would really hate to see completely mechanical drivetrains on bicycles disappear altogether. That would be really sad.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

by Weenie


User avatar
TonyM
Posts: 3259
Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

Electric is certainly easier for many but then if you change the wheelset then you have to adjust the RD accordingly..
If you change also the gearing of the cassette then you still have to adjust the B screw, change the gearings in the app so it is correctly displayed in the Garmin etc...

AND don't forget all the firmware updates etc....that should be done....

So electric is definitely not a 0% maintenance also.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post