DI2 bar end junction without holes in bar

Discuss light weight issues concerning road bikes & parts.
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gbrown
Posts: 32
Joined: Sat Mar 11, 2017 4:35 pm

by gbrown

I've just bought a new Trek Domane SLR 9 Disc with R9170 di2 and the shop are prepping it for collection. The mechanic has fitted a bar end junction, even though the Bontrager carbon bars aren't drilled, by taking a single di2 wire down the underside of the bar to the right shifter. I popped in today to take a look before the bar was wrapped, and grabbed some photos.

So he's used a single short cable, taken from the under stem junction box no longer being used, to run from the bar end junction, looped it back inside the bar end and squeezed it down the side of the junction box and then looped round and taped it under the bar to run up to the shifter. The bar tape will then completely cover it.
di2barend.jpg
He then used a y-cable to run the long ends between the shifters along the outside of the bars as normal, along with the hydraulic brake cables. The short tail of the y cable will be tucked into the stem, through the opening under the bar and connected to the WU111 wireless unit. The cable from the bottom bracket that went to the old junction box will then also be tucked into the stem so it will all be very neat and tidy.

My first thought was that the cable would be crushed or pinched when squeezed between the bar end and the bar, and turned sharply back on itself, but all seems to work well and passed all diagnostics. Once taped up, it should look very neat.
di2barend2.jpg
Has anyone else done it this way?

Cheers,

Geoff

by Weenie


pdlpsher1
Posts: 1751
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Yes. There are several videos on YouTube describing this method. But this is the first time I’ve seen a wire go inside the bar not via a small hole drilled near the end of the bar. I had considered this method but ultimately I decided to drill two holes on my bar.

Congrats on your new bike.


Sent from my iPhone using Tapatalk

rlanger
Posts: 76
Joined: Sun Oct 02, 2016 11:53 am

by rlanger

gbrown wrote:
Mon Feb 05, 2018 5:46 pm
I've just bought a new Trek Domane SLR 9 Disc with R9170 di2 and the shop are prepping it for collection. The mechanic has fitted a bar end junction, even though the Bontrager carbon bars aren't drilled, by taking a single di2 wire down the underside of the bar to the right shifter. I popped in today to take a look before the bar was wrapped, and grabbed some photos.

So he's used a single short cable, taken from the under stem junction box no longer being used, to run from the bar end junction, looped it back inside the bar end and squeezed it down the side of the junction box and then looped round and taped it under the bar to run up to the shifter. The bar tape will then completely cover it.

di2barend.jpg

He then used a y-cable to run the long ends between the shifters along the outside of the bars as normal, along with the hydraulic brake cables. The short tail of the y cable will be tucked into the stem, through the opening under the bar and connected to the WU111 wireless unit. The cable from the bottom bracket that went to the old junction box will then also be tucked into the stem so it will all be very neat and tidy.

My first thought was that the cable would be crushed or pinched when squeezed between the bar end and the bar, and turned sharply back on itself, but all seems to work well and passed all diagnostics. Once taped up, it should look very neat.

di2barend2.jpg

Has anyone else done it this way?

Cheers,

Geoff
Have you had any issues with this setup Geoff? Looking to do this on my bike next week.

Thanks.

gaspard123
Posts: 5
Joined: Wed Nov 08, 2017 6:07 pm

by gaspard123

thought I would give this one a bump to check on long term durability of this solution. Most of the traditional bars I'm interested in are not yet drilled, and while I'm not entirely opposed to getting the drill out, was just curious if this one had worked out. thanks in advance

Dokas
Posts: 23
Joined: Thu Jun 02, 2016 2:12 pm

by Dokas

The di2-line does not appear to be good for the possibility of being cut in the event of a collision

avispa
Posts: 255
Joined: Tue Mar 11, 2008 2:36 am

by avispa

If I’m not mistaken, this is the way it’s done with non-drilled bars. And one reason Shimano provides a “dummy” cable with the EW-RS910 so that a mechanic installs it on the opposite side of the bars and the rider does not feel as if one side there’s a cable and on the other the bars would feel smooth.

One reason some frames also have a second installation location for the RS910, such as the down tube, is to clear the bars from junction boxes.

I think in case of a collision where your bar ends take the brunt of the impact the RS 910 most likely would be damaged.

There’s really no risk on drilling holes in bars or frames. The only thing is that it voids warranties and nobody wants to take responsibility (rightfully so) for possible problems .

by Weenie


bedampft
Posts: 16
Joined: Wed Jul 18, 2018 8:04 pm

by bedampft

gbrown wrote:
Mon Feb 05, 2018 5:46 pm
I've just bought a new Trek Domane SLR 9 Disc with R9170 di2 and the shop are prepping it for collection. The mechanic has fitted a bar end junction, even though the Bontrager carbon bars aren't drilled, by taking a single di2 wire down the underside of the bar to the right shifter. I popped in today to take a look before the bar was wrapped, and grabbed some photos.

So he's used a single short cable, taken from the under stem junction box no longer being used, to run from the bar end junction, looped it back inside the bar end and squeezed it down the side of the junction box and then looped round and taped it under the bar to run up to the shifter. The bar tape will then completely cover it.

di2barend.jpg

He then used a y-cable to run the long ends between the shifters along the outside of the bars as normal, along with the hydraulic brake cables. The short tail of the y cable will be tucked into the stem, through the opening under the bar and connected to the WU111 wireless unit. The cable from the bottom bracket that went to the old junction box will then also be tucked into the stem so it will all be very neat and tidy.

My first thought was that the cable would be crushed or pinched when squeezed between the bar end and the bar, and turned sharply back on itself, but all seems to work well and passed all diagnostics. Once taped up, it should look very neat.

di2barend2.jpg

Has anyone else done it this way?

Cheers,

Geoff
Only problem with this setup is, you can't use extra shifters on one of the STIs.

I'm going to drill one hole near the barend in my Easton Carbon Dropbar tomorrow. Then i'll route one short wire on the outside of the bar to the right STI and the Y-cable between the other STI and the bar end junction. In this case i still got one port left on each STI for extra shifters. But i'm still a little mad that Shimano has lost the sprinter ports on the ST-R9170.

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