di2 install tips - aero handlebar

Discuss light weight issues concerning road bikes & parts.
buhx2
Posts: 23
Joined: Mon Mar 06, 2017 5:05 pm

by buhx2

I'm currently in the process of building up my first frame (2018 Cervelo S5) using R8050 di2, and having a hard time getting the di2 wires through my aero handlebar internally (Cervelo aero handlebar). There's pre-drilled holes for shifters, brake cables to exit the handlebar, and a hole in the middle of the handlebar where the stem attaches. Any tips on how to feed the cables through? Using the RS910 handlebar junction box, and my plan was to go from

junction a->right shifter
right shifter->left shifter
left shifter->junction b
junction b->d fly
d fly->battery
junction b->FD
junction b->RD

No issues getting the wiring through the frame which is all done, but cant even get one wire through the handlebar for the connections I need, let alone 3 connections in the handlebar. Any tips on how to internally wire or cable a handlebar getting through the kinks? I imagine I'll go through the same frustrations with brake cables.

Schadenfreude
Posts: 33
Joined: Sun Feb 10, 2019 10:47 pm

by Schadenfreude

buhx2 wrote:
Thu May 23, 2019 5:49 am
Any tips on how to internally wire or cable a handlebar getting through the kinks? I imagine I'll go through the same frustrations with brake cables.
I'm not sure about the brake cables, but for the di2 cables I got some strong, but thin twine and used a a vacuum cleaner to pull it through the handlebars. I then taped the di2 cable to the end of the twine (tape behind the di2 cable plug so it has some grip with the twine) and carefully pulled it through using the twine. At times, I had to tug the twine quite hard, but you want to be careful not to damage the di2 cable, but I didn't seem to have any issue with that. I only have a set of alloy bars, which I drilled holes in the drops for the cables, so I guess there may be some additional challenges with the aero bars and brake cables.

by Weenie


scale29
Posts: 118
Joined: Sat Jun 04, 2011 5:40 pm

by scale29

To thread Di2 wires, I made up a draw wire.

Grab a gear cable (remember those) and a 4mm gear ferrule, put the cable through the ferrule backwards, so that the nipple on the cable is inside the ferrule then cut the blank end off a cable crimp, slide over the wire to the ferrule, and crimp.

The 4mm ferrule is a snug but easily connected, holder for a Di2 plug. The steel wire pushes through bars and frames easily and can be caught with magnets etc for tricky areas, a little ‘set’ on the end of the cable can help it exit holes.


hambini
Posts: 460
Joined: Tue Nov 15, 2016 8:13 am
Location: Bristol UK / Cologne, Germany

by hambini

I'd recommend welding wire to thread the wires through. It's flexible enough to go round the bends and rigid enough to poke.
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jmechy
Posts: 43
Joined: Wed Jun 04, 2008 3:18 am

by jmechy

I used floss with a small weight tied to the end for my Aerofly IIs. Then I was able to move the bars around and use gravity to pull the weight down until it came out the other end. Just make sure you pull another piece of floss through if you need to do two cables through the same run

DeeHubbs
Posts: 99
Joined: Tue Mar 31, 2015 11:05 pm

by DeeHubbs

Dental floss and a shop vac.

buhx2
Posts: 23
Joined: Mon Mar 06, 2017 5:05 pm

by buhx2

Tried the vacuum trick with dental floss last night but no go. I’ll try the welding wire tonight and if that doesn’t work I’ll try the floss with weight. Thanks for the suggestions.

beanbiken
Posts: 701
Joined: Tue Mar 18, 2014 10:13 pm
Location: Great Southern Land

by beanbiken

I've had success using gear cable liner, the thin teflon[??] stuff initally then followed by string/cable whatever. Doesn't work every time though so then try the vacumn idea or string/floss with a folded piece of masking tape on the end then a air blower to blow the tape/string through the bar............
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Coffee & carbon

dricked
Posts: 181
Joined: Tue Jan 09, 2018 1:57 pm

by dricked

Gear cable, a strong magnet, and some small pics or something of the sort. It can be a pain in the ass.

buhx2
Posts: 23
Joined: Mon Mar 06, 2017 5:05 pm

by buhx2

spent 2 hours on it last night, got the weld wire about 3/4 the way through the bar trying to go shifter to shifter. Taped it up and give it another go tonight. This bar seems like there's so many rough edges on the inside, the wire seems to get caught on everything. Hopefully going shifter to shifter is the hardest one.

dricked
Posts: 181
Joined: Tue Jan 09, 2018 1:57 pm

by dricked

I tried using a fine wire too, it was awful. The shifter cable doesn't get caught up on small imperfections and you can also direct it with a magnet easier to get it out of the holes.

jmechy
Posts: 43
Joined: Wed Jun 04, 2008 3:18 am

by jmechy

buhx2 wrote:
Fri May 24, 2019 7:07 pm
spent 2 hours on it last night, got the weld wire about 3/4 the way through the bar trying to go shifter to shifter. Taped it up and give it another go tonight. This bar seems like there's so many rough edges on the inside, the wire seems to get caught on everything. Hopefully going shifter to shifter is the hardest one.
On my aerofly II's I didn't go shifter to shifter directly. I ran a shifter to stem cable, then the other shifter to stem cable, then tied them together. Not sure if that will work for your bars, but definitely made it much easier for me as the holes on the shifter side were small but the stem holes were large and made for easy targets to send a cable to.

Hexsense
Posts: 801
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

I find Aerofly II really really easy to route shifter to shifter. And also shifter to bar end junction box.
literally 2 minutes with park tool internal routing kit to do it.

Maybe i learned a lot from a much harder to route, Enve SES Aero road bar (routing both di2 and mech cable). It was much harder to route than Aerofly II.

Bogan
Posts: 281
Joined: Tue Feb 11, 2014 11:47 pm
Location: Boganville, Australia

by Bogan

I did some Aerofly II bars with Di2 and Alligator iLink brake cabling using a Park Tool Internal Routing kit as well. No real dramas.
MAMIL? Never. O.F.I.L. yeh! (Old F**ker in Lycra)

by Weenie


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