Di2 shifter to shifter connection...possible?

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mr4fox
Posts: 276
Joined: Sat May 15, 2010 2:01 pm

by mr4fox

Before I go untaping my bars and removing cables and shifters to test this can anyone tell me for sure if connecting one di2 shifter directly to a spare port in the other di2 shifter will or won't work?

If it does then I can run a single cable back (through the hole in the top tube that's only big enough for a single di2cable) to the junction A box which I am hoping to relocate inside the seat tube.

Dfly will let me trim the derailleur if necessary and check battery status so I'd only need to remove the seat post to charge the batter every few weeks.

Raineman
Posts: 185
Joined: Mon Oct 06, 2014 2:03 pm
Location: Kent, UK

by Raineman

Should work, as long as everything is connected Di2 doesn't seem to really care where anything is plugged in. I think some other WW have already done this.

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goodboyr
Posts: 1488
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

How do you adjust the derailleur with dfly but without access to the junction a adjustment button? You need the button to get it into adjustment mode.

mr4fox
Posts: 276
Joined: Sat May 15, 2010 2:01 pm

by mr4fox

hmm you got me. Lol! I thought I could set a long press of one of the hidden buttons on top of the hoods to open the gear trim page on my garmin....seems it's not an option.

But regardless...it's so infrequent I need to adjust it I'm not concerned about accessing it. I'd still prefer a nice clean front end and to just remove tye seat post to charge and trim gears.
Thanks for pointing that out though.

Danza
Posts: 134
Joined: Thu Jun 27, 2013 12:41 pm

by Danza

Check the BMC TMR Di2 thread, I think they ran shifter to shifter, then had junction A hidden at the top of the seatpost.

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53x12
Posts: 3708
Joined: Fri Sep 15, 2006 6:02 am
Location: On the bike

by 53x12

Yes, you could run right shifter to left shifter, left shifter into downtube and to the junction box...etc.

One idea that I saw online that I like, put the junction A box by the FD under the water bottle. Would still have easy access to charge it, do diagnostics and trim while riding.


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HTML
Posts: 41
Joined: Sat Feb 21, 2015 11:37 am

by HTML

What if your water bottle leaks and it runs down and into the junction box ? how waterproof are they ?

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53x12
Posts: 3708
Joined: Fri Sep 15, 2006 6:02 am
Location: On the bike

by 53x12

Pay the $6 and get a new water bottle. You deserve it.

The junction box is fine. Been fine riding in rain, washing bike and having bike on the roof driving through a rain storm.
"Marginal gains are the only gains when all that's left to gain is in the margins."

Raineman
Posts: 185
Joined: Mon Oct 06, 2014 2:03 pm
Location: Kent, UK

by Raineman

I would be temted to put one of the dummy plugs in the empty socket just to protect it but you are probably fine like that

AndreLM
Posts: 479
Joined: Tue Feb 05, 2013 11:53 pm

by AndreLM

WheresWaldo here in the forum created some cool 3D-printed mounts for the Di2 Junction-A.

You can use this one and some mounting tape.

Or... if you are lucky and your frame has provision for the external battery in the downtube, you can use this other one.

goodboyr
Posts: 1488
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

kova3023 wrote:How do you adjust the derailleur with dfly but without access to the junction a adjustment button? You need the button to get it into adjustment mode.

Great question.....already asked and answered earlier in this thread.......

Jesper64
Posts: 71
Joined: Sat Aug 30, 2008 1:16 pm

by Jesper64

Also, what happens if you crash and the derailer goes into protection mode. To release it out of protection mode you need to hold down the A junction button.

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Grill
Posts: 662
Joined: Mon Aug 20, 2012 12:12 pm
Location: Oop North

by Grill

I have my A junction in the head tube. To charge or adjust I just use a second A junction and plug it between the rear mech and cable.

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