Ultegra Di2 ST-R785 LEFT lever can shift Rear Derailleur?

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andreszucs
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by andreszucs

Hello, I'm new to Di2, recently got a 2x11 Ultegra Di2 6870 equipped bike but I converted to 1x11, now I am wondering if I can just re- route the cable coming from the RD to the left lever and make it work? Reason is because I'm missing a couple of finger on my right hand and I would have more control if I can shift and brake all with the left side.

Is there any additional steps to do this such as configure the left lever thru a software using a computer?

Thanks
Last edited by andreszucs on Thu Jul 06, 2017 5:48 pm, edited 1 time in total.

by Weenie


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andreszucs
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by andreszucs

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Last edited by andreszucs on Thu Jul 06, 2017 5:48 pm, edited 1 time in total.

morganb
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by morganb

You can but it isn't done with the wire routing. You need to use the etube software to change what the buttons control on the shifter.

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FIJIGabe
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by FIJIGabe

You don't need to re-route the wiring. What you want to do can be handled via the e-tube software. You can customize all of the buttons to do different things.
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andreszucs
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by andreszucs

Since I took the Front Derailleur out, the left lever is now disconnected, the cable is still there but hanging where the FD was down the BB, so I'm a little confused?!

morganb
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by morganb

andreszucs wrote:Since I took the Front Derailleur out, the left lever is now disconnected, the cable is still there but hanging where the FD was down the BB, so I'm a little confused?!

The left lever should go to the Junction A box, which then routes to the Junction B, which then routes to both derailleurs. You're left shifter shouldn't be directly connected to the FD.

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andreszucs
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by andreszucs

morganb wrote:
andreszucs wrote:Since I took the Front Derailleur out, the left lever is now disconnected, the cable is still there but hanging where the FD was down the BB, so I'm a little confused?!

The left lever should go to the Junction A box, which then routes to the Junction B, which then routes to both derailleurs. You're left shifter shouldn't be directly connected to the FD.



Haha that was funny, my brain is still on 30 years riding mechanical a guess, lol...where there is no junction!

Okay so...what If I unplug the cable ending on the right lever and re-route it to the left lever keeping it on the same port at the junction (the box under my stem)? From what I understand the box is the one configured to assign each port to a function...so in theory that would work?

jano
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by jano

No, that is not how it is working. You need to re-program the buttons on the shifter so they send the right signal to the right component, in this case your rear derailleur.

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FIJIGabe
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by FIJIGabe

E-tube Di2 is not port dependent. You can plug any device into any port, and it will work as directed by the firmware. You just need to reprogram the shifters using the e-tube program. You may want to remove the wire you pulled from the FD, however, and cap off the port, to prevent water from getting in there.

As a side note, by upgrading to the latest firmware, you can "control" the front and rear derailleurs from the same shifter. Just enable the syncro-shift option, and by shifting, Di2 will go to the next easiest or hardest gear, shifting both the front and rear derailleurs to find the setting. This way, you can pretty much just use your right lever for braking.
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wingguy
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by wingguy

andreszucs wrote:Okay so...what If I unplug the cable ending on the right lever and re-route it to the left lever keeping it on the same port at the junction (the box under my stem)? From what I understand the box is the one configured to assign each port to a function...so in theory that would work?

No, to be blunt your understanding is completely wrong. The junction box does not work that way. The right shifter can plug into any port and the system still knows that it is the right shifter. The left shifter can be plugged into any port and the system still knows it's the left shifter.

You have to reprogram it with the etube software to tell it what you want the left hand shifter to do. Once you have told the system that you want the left hand shifter to control the RD that's it. That's what the left hand shifter will do, regardless of where you plug it in. You can even keep the right hand shifter plugged in and controlling the RD as well if you want to.

We customised a bike for someone who only had one hand where we programmed the left shifter to work the RD, then put a climb shifter on the left hand drop to work the FD. All doable through etube software.

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andreszucs
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by andreszucs

wingguy wrote:
andreszucs wrote:Okay so...what If I unplug the cable ending on the right lever and re-route it to the left lever keeping it on the same port at the junction (the box under my stem)? From what I understand the box is the one configured to assign each port to a function...so in theory that would work?

No, to be blunt your understanding is completely wrong. The junction box does not work that way. The right shifter can plug into any port and the system still knows that it is the right shifter. The left shifter can be plugged into any port and the system still knows it's the left shifter.

You have to reprogram it with the etube software to tell it what you want the left hand shifter to do. Once you have told the system that you want the left hand shifter to control the RD that's it. That's what the left hand shifter will do, regardless of where you plug it in. You can even keep the right hand shifter plugged in and controlling the RD as well if you want to.

We customised a bike for someone who only had one hand where we programmed the left shifter to work the RD, then put a climb shifter on the left hand drop to work the FD. All doable through etube software.


Ok thank you for the clarification!

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