# ultegra di2 installation on Cr1 pro 2012



## hammermc (Aug 7, 2010)

I'm in the process of upgrading my CR1 pro to ultegra di2. I'm stuck on how to attach the external rear junction (part sm-jc40) to the underside of the bottom bracket. 

The junction is supposed to screw onto the underside of the bottom bracket where the cable guide usually does. However the cable guide on this frame is attached by double sided tape only. 

I'm thinking of trying double sided tape but not sure if it's going to be secure enough. Has anyone else figured out how to get the junction to attach securely?


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## z85guy (Apr 25, 2011)

Great question. I was pondering this upgrade and thinking the same. Look forward to some replies. I know the sticky tape is pretty good so i wonder if its some industrial brand. Im probably going to my LBS this weekend and Ill ask.


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## pumaking (Nov 29, 2009)

You're going to have to use the bottle cage battery mount.


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## pumaking (Nov 29, 2009)




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## z85guy (Apr 25, 2011)

Ive been checking and found this link. This guy's lbs mounted the internal box externally. The pro would be more surface area against the BB or other places. Con.. how water proof and what to do with excess cable? Another guy mentioned industrial velco. The external junction box has a limited area to adhere it to with the limited contact area due to the cable wrapping grooves. I saw anothe post where a guy also used the intenal externally on his Cervelo p2.

[URL="http://www.cyclingforums.com/t/490780/frame-for-di2-internal-set-up-cant-take-the-cables-inside"[/URL]

Hope this helps and if you got DI2 keep us posted.


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## HomerJ (Sep 25, 2012)

Reviving an old thread, but am facing the same problem. Curious how others have done it.


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## maldin (Sep 13, 2013)

Also reviving the thread in the hope that someone who faced this problem has resolved it? 

I am considering either trying to hotglue the external junction on to the frame, or using sticky tape velcro to hold the internal junction on the outside of the downtube and the bundling up the cables and using a velcro patch to attach those that to the frame as well. Perhaps not entirely as elegant as the proper external junction, but I am concerned I won't be able to find a way to attach that... has anyone actually found a working solution?


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## maldin (Sep 13, 2013)

For what it is worth to future readers, I have decided to concoct something with velcro which will be hopefully both strong enough to hold the bike indefinitely yet also easy to take off and adjust, just as it would have been had our frames had the screw in cable guide Shimano expected. Basically its sticky velcro tape with the soft side wrapped around the junction box on 3 sides, then on the top side where the cables would run, I have stuck a rectangle of plastic to ensure the cables are not stuck to the tape, then the soft velcro continues to wrap around the 3 sides of the junction box again. For the length of the last 3 sides of the box, I cut a piece of hook velcro of the same length and stuck it to the soft velcro, sticky side to sticky side. In turn, hook velcro length can then also stick, using the velcro hooks, to the 3 sides of the junction box. The pictures will make the description clearer. The end result of that the velcro is firmly attached to the junction box, I can tuck the loose wires into the area of the box Shimano intends, then fold the loose (not glued/stuck) velcro flap over the wires holding them in place and strap it all down to itself using the last section of the strap with the hook velcro to the soft velcro. 

In turn I can attach the whole contraption to a single piece of hook velcro attached to the underside of the bike. It is easy to take everything off the bike, dismantle and readjust the wires if necessary yet everything is held securely on the bike the rest of the time. I think this is better than the alternative options I considered using glue or double sided sticky tape which seemed either semi permanent (messy if you wanted to adjust the wires) or not permanent enough (I am not sure there is enough surface area for double sided sticky tape?). I hope this helps someone in the future if they have the same conundrum as myself in the future.


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