Ultegra 6870 di2 Rear Shifting Problem

[hlvd]

I wonder if someone could help with a problem I've got with Ultegra 6870 di2 rear shifting.

The rear shifter's gear change seems to vary depending on how positive a click I give it, leading to a poor change if I don't press the front lever/button behind the brake lever positively.
This happens going up the cassette into the low gears, but doesn't happen when dropping a cog going dow the cassette into the high gears.

Is this normal as it's been like this since installed in March 2016?

[glepore]

Its not "normal" but its not uncommon with Ultegra and certain installs, particularly if there's any friction at all in the path-ie if the cables are installed so that they cross in the downtube, or if there are tight bends in the housing.

[hlvd]

Its not "normal" but its not uncommon with Ultegra and certain installs, particularly if there's any friction at all in the path-ie if the cables are installed so that they cross in the downtube, or if there are tight bends in the housing.

Hi, this is on a di2 install, I'll update the title, thanks.

[glepore]

My bad. Obviously 6870 is di2. Either the switch makes contact or it doesn't.

[Multebear]

Have you autoadjusted? And are the outer and inner limit adjusted as well?

[hlvd]

Have you autoadjusted? And are the outer and inner limit adjusted as well?

I'll check the high and low limit and see if there's a difference.
I had everything installed at my local shop and I've complete confidence in them as they're top guys, so doubt it's an installation issue.

[hlvd]

I've checked the high and low limit screws and things seem fine.

I'm using an SRAM Force 1170 chain with the group, would a Shimano chain improve the shifting?

[wheelsONfire]

* How long is the chain?
(Too short, too long?)

*The RD derailleure handger is aligned and straight`

*It is not loose or badly torqued?

It's easy to adjust to electrical settings.
But if it is not constant in what it does it could be something like above suggested.

[Multebear]

I've checked the high and low limit screws and things seem fine.

I'm using an SRAM Force 1170 chain with the group, would a Shimano chain improve the shifting?

Set the chain in the small chainring and 3 gear on the cassette (3. lowest gear). Start pedaling, and press and hold the button under the junction box until the rear derailleur starts shifting. Keep pedaling until the rear derailleur is in the lowest gear. That is how you auto adjust. If you haven't done this, you don't know if you gears are adjusted.

[hlvd]

I've checked the high and low limit screws and things seem fine.

I'm using an SRAM Force 1170 chain with the group, would a Shimano chain improve the shifting?

Set the chain in the small chainring and 3 gear on the cassette (3. lowest gear). Start pedaling, and press and hold the button under the junction box until the rear derailleur starts shifting. Keep pedaling until the rear derailleur is in the lowest gear. That is how you auto adjust. If you haven't done this, you don't know if you gears are adjusted.

It doesn't mention this in the Shimano Dealer Techdocs website, does this work??

[goodboyr]

That's not an "auto adjust". It's for when you've had an impact to the Rd and need to reset the fail safe linkage. Has nothing to do with adjusting.

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[hlvd]

That's not an "auto adjust". It's for when you've had an impact to the Rd and need to reset the fail safe linkage. Has nothing to do with adjusting.

Sent from my SM-G900W8 using Tapatalk

Thanks for clarifying that.

I've tried to adjust the indexing and it's maybe better. One thing I've noticed is that I can get a perfect shift when my right foot is at the 6 o'clock position, not so at the 12 o'clock.
I've never noticed this before, make any sense?

[goodboyr]

Maybe check for play in your crank. I suppose if there's movement at the chainring, it might affect the rear shift. But that's a long shot. Grasp the two crank arms and try to wiggle them. There should be no play.

Sent from my SM-G900W8 using Tapatalk

[hlvd]

Maybe check for play in your crank. I suppose if there's movement at the chainring, it might affect the rear shift. But that's a long shot. Grasp the two crank arms and try to wiggle them. There should be no play.

Sent from my SM-G900W8 using Tapatalk

I'll check that, thanks.

[Multebear]

That's not an "auto adjust". It's for when you've had an impact to the Rd and need to reset the fail safe linkage. Has nothing to do with adjusting.

Sent from my SM-G900W8 using Tapatalk

Well, that's how I've done it whenever I've changed wheelsets. And everyone that I know, does the same. And it works everytime. I've done it ever since I got the bike two years ago. I've even seen my LBS mechanic use that trick as well.