Di2 wire lengths

Discuss light weight issues concerning road bikes & parts.
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vinuneuro
Posts: 103
Joined: Mon Mar 06, 2017 10:34 pm
Location: Chicago

by vinuneuro

Could someone kindly confirm if the wire lengths I have are correct? This is from a Specialized rep but they are not matching up with what I've found online. For a 56cm frame 2016 Diverge which is near identical dimensionally to the Roubaix.

Downtube 1000mm etube (seems 50mm long?)
FD - 500mm (seems 100mm long?)
Shifters 2x 350
RD 700 or 750 (seems 100-150mm long?)
Battery to Juction B 1000mm (?)
'16 Spec Diverge Expert

kode54
Posts: 1210
Joined: Tue May 23, 2006 9:39 pm

by kode54

depends if you decide to incorporate the handle bar end junction. if that's the case, you'll need a longer wire from junction B to shifter or bar end junction.

what junction do you plan to use? A or the handle bar end one?
- AX Lightness Vial EVO D + DA9150 + Enve SES 3.4 carbon hubs
- Parlee Altum + DA9150 + Enve SES 4.5 carbon hubs
- Parlee ESX + DA9150 + THM SRM PM + Enve SES 6.7 CK hubs
- Independent Fabrication Ti FLW + DA9100 + Enve 3.4 CK hubs

by Weenie


vinuneuro
Posts: 103
Joined: Mon Mar 06, 2017 10:34 pm
Location: Chicago

by vinuneuro

Probably A. I already have a carbon bar and don't want to buy another one just for this.
'16 Spec Diverge Expert

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IrrelevantD
Posts: 287
Joined: Sun Nov 29, 2015 5:47 pm
Location: Near DFW Airport

by IrrelevantD

If it’s cabled internal, I prefer to go a little long. Not like a couple hundred mm is going to hurt you that much in weight, and any slack is hidden inside the frame.
* There is a 70% chance that what you have just read has a peppering of cynicism or sarcasm and generally should not be taken seriously.
I'll leave it up to you to figure out the other 30%. If you are in any way offended, that's on you.

Rob1519
Posts: 55
Joined: Thu Mar 17, 2011 7:29 pm

by Rob1519

The reps recommendations are fine. No penalty to being a little long but too short is a pain. If bars are wider than 44, you may want to increase the A to shifter lengths.

Cemicar
Posts: 46
Joined: Mon Aug 21, 2017 7:40 am

by Cemicar

If your concern about longer wires is those weights, never mind them. Those cables only add less than 1 gram per 100mm. Rather, care about the case where any of your cables is too short. It costs $30 or so.

vinuneuro
Posts: 103
Joined: Mon Mar 06, 2017 10:34 pm
Location: Chicago

by vinuneuro

My concern is extra wire length rattling inside.
'16 Spec Diverge Expert

Rob1519
Posts: 55
Joined: Thu Mar 17, 2011 7:29 pm

by Rob1519

vinuneuro wrote:
Wed Jan 24, 2018 4:41 pm
My concern is extra wire length rattling inside.
If there is cable rattle, Shimano produces a cable (SD-501) tie that attaches to the wire and lightly presses against the inner wall of the bike tubing.

The only rattling I ever had was from an internal B junction. Solved with a little foam.

kode54
Posts: 1210
Joined: Tue May 23, 2006 9:39 pm

by kode54

before Shimano made the reusable cable ties, regular cable ties were recommended, leaving the tail on it instead of trimming it like usual. the reusable ones are nice since you can move them around the length of the wire.

too short wire may disconnect from ports when stressed. better to have slack to take up some of the pull when turning handlebars, etc.
- AX Lightness Vial EVO D + DA9150 + Enve SES 3.4 carbon hubs
- Parlee Altum + DA9150 + Enve SES 4.5 carbon hubs
- Parlee ESX + DA9150 + THM SRM PM + Enve SES 6.7 CK hubs
- Independent Fabrication Ti FLW + DA9100 + Enve 3.4 CK hubs

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IrrelevantD
Posts: 287
Joined: Sun Nov 29, 2015 5:47 pm
Location: Near DFW Airport

by IrrelevantD

vinuneuro wrote:
Wed Jan 24, 2018 4:41 pm
My concern is extra wire length rattling inside.
as others have mentioned, just get a handful of small zip ties slightly longer than the diameter of the tube. They're cheap, space them out a few inches a part and they'll pretty much hold the cables in place inside the tube and keep them from rattling. I'm even using that technique to keep my Bluetooth/ANT+ unit in place inside the frame. Works like a champ.
* There is a 70% chance that what you have just read has a peppering of cynicism or sarcasm and generally should not be taken seriously.
I'll leave it up to you to figure out the other 30%. If you are in any way offended, that's on you.

by Weenie


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