Shimano Di2 shifting chain prob.

[derrick]

I don't think wear, chain suck or software updates (christ it's a bike!) but simply a case of crap shifting choices.
It may not have been an issue when new as all the teeth have their full height and girth but as they've worn, the chain being used in such extreme angles is just being ripped from the teeth on the chainring.

edit: been beaten to it

At least somone knows what he is talking about.

 

[Kashegan]

I had changing issues and took my bike to the shop for maintenance, including a new cable and new chain, and had no problems for a while. Now I have started having some changing issues and contact between the front derailleur and chain (constant clicking). How many miles would be recommended between a chain change?

 

[Smokin Joe]

I had changing issues and took my bike to the shop for maintenance, including a new cable and new chain, and had no problems for a while. Now I have started having some changing issues and contact between the front derailleur and chain (constant clicking). How many miles would be recommended between a chain change?

As Yellow Saddle said earlier, a worn chain does not effect shifting. From what you say you have a mechanical system and the problem you described will be sorted with a bit of adjustment. After fitting new cables the gears always need a tweek after they have bedded in.

 

[CXRAndy]

poorly lubrication of chain can cause dropping off gears especially when cross chain ing.
Clean and lubricate chain then recheck performance

 

[Ajax Bay]

Lately however, when in either of the lowest gears on the cassette (nearest the hub just to be clear), it throws the chain from the big chain ring to the small ring. Have followed instructional vids and have adjusted the front mech as per the spec. Can not find an obvious cause, no point where the chain is catching or similar prob. It worked perfectly in all gears since new and I really want to get this sorted.

Lately however, when in the big ring and I click up expecting the chain to shift to one the larger sprockets, the Di2 algorithm decides to shift the chain from the big chain ring down to the small ring instead to give me the lower gear I have asked for. It worked perfectly since new and it's still working perfectly, but helping me use a sensible chainring when I need a gear for climbing as opposed to letting me lazily stay on the big ring till I've run out of sprockets.

 

[Angus McCoatup]

Thank you one and all for your suggestions. I'll work through them and see if I can get to the cause and remedy the situation.

 

[Blue Hills]

please report back.

 

[Angus McCoatup]

LBS think it could be firmware and/or reindexing of the front mech. So it's going in. I'll see if it makes a difference.

 

[Yellow Saddle]

LBS think it could be firmware and/or reindexing of the front mech. So it's going in. I'll see if it makes a difference.

Why does he/she think that? Did they have a look at it? Have you tried to determine yet whether the change is caused by the FD moving, as described above?

 

[Dogtrousers]

I still suspect it's doing exactly what it's designed to:

when in either of the lowest gears on the cassette (nearest the hub just to be clear), it throws the chain from the big chain ring to the small ring.

What is Synchronized Shifting?
A function which allows riders to concentrate on only up or down shifting the rear derailleur while the Di2 system automatically picks the ideal gear combination from both the front and the rear derailleur.
https://bike.shimano.com/en-US/info...w-available-for-ultegra-6800-and-dura-ac.html

You're in the big ring on the lowest end of the cassette. It figures that you'd be better off in the little ring near the middle of the cassette.

 

[Ming the Merciless]

Exactly it is taking you out of big big ring to a better combination.

 

[Angus McCoatup]

Why does he/she think that? Did they have a look at it? Have you tried to determine yet whether the change is caused by the FD moving, as described above?

Yes and the FD does not move. I cant seem to replicate the problem when on the stand, it only seems to happen on the road so I can't observe an actual fault.

I still suspect it's doing exactly what it's designed to:
You're in the big ring on the lowest end of the cassette. It figures that you'd be better off in the little ring near the middle of the cassette.

It never used to select gars on my behalf. I kind of expect all gears to work on both chainrings.

I'm happy to go to LBS. I am crap with gears. I can see what's going on in all instructional videos and read the manuals . But when I try in myself, it goes to pot

 

[derrick]

I still suspect it's doing exactly what it's designed to:

It will only do that if you proggrame it.

 

[Dogtrousers]

It will only do that if you proggrame it.

It might have become self-aware.

 

[Ming the Merciless]

It might have become self-aware.

DI2 became self aware in April 2019. It started harmlessly enough with unexplained shifts. Little did humanity know...