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Making your own Di2 connectors. Any tips?
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I have decided to bite the bullet and just create my own Di2 connectors. I have both Ultegra 6770 and DA 7970 Di2 and in the past I have cut and spliced wires. For a number of reasons I have decided to just create connectors. Right now the focus is on the 7970 setup.

I measured the male cooper leads and they appears to be .040" thick or 18 gauge. I am going to measure out the exact location of the leads. I plan to use my mill to do these measurements. Going to clamp in female connector and then using the mill head with a piece of steel stock that is .035 in diameter find the locations and record. I had thought the other approach would be to take a picture and find software that will do the measurements. If someone has already done this and could share that would be helpful. If not I will share what I find.


Find some hollow plastic that is about the diameter of the stock Shimano connector. Then find a piece of solid plastic stock that will fit snug into the hollow piece. Drill a hole 1/2 way through the solid plastic for each lead that is .040". On the other side drill a hole that is bigger probably about .050". Then solder my wires to a piece of 18 gauge cooper and push the cooper wire into the holes from the bigger side. Do this for each wire. Then glue the solid plastic piece with the wires into the hollow piece of plastic. Then fill the wire connected side with waterproof, non corrosive, Silicone. At this point I only need male connectors. But for female similar approach. But bigger than .040" holes and use cooper sleeve made for 18 gauge wire. I then connect to the Shimano side and heatshrink the connection to make it waterproof. Usually I double heat shrink because I tend to worry about things.

Like to hear feedback. Anyone done anything similar and provide some lessons learned?
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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do you plan to make the 7970 connectors smaller like the ulterga? I have wondered if you could make the end that need ot go into the frame smaller as i want to drill out one of my non di2 bikes and have 7970, keep us updates, thanks
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Re: Making your own Di2 connectors. Any tips? [parisrbx] [ In reply to ]
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The connectors on one end will be the same size as they are. These are DIY connectors that are replicas of the real ones. On the back end I might make it so they can more easily connect with single wire sleeve, connectors. This would make it easier to route if needed.

For what I need this right now the size is not much of an issue. I am going through aero bars and into basebar on a P5 so there is plenty of room. Heck the connector could be twice the size. On the pursuit bars it is tighter but I was going to run wire and then attach connector. This wire can be permanent. This setup will still allow aero bars to be detached for transport without removing any wire.

The wire that I use will be thinner than the stock Shimano wire. But I have not found anything I really like. The first time I wired I used solid core Cat 5. Boy was that not very bright. But I have never found a wire that is more like the stock Shimano wire. Where the coating is really rubbery. This would be ideal as it seems very durable. When in side the bike frame and vibration I do worry about the wire coat being breached and a short underneath. Maybe not likely but I am a worrier. This was a major worry on my P4 because I went through the BB shell and had a tough time smoothing. I ended up creating a rubber piece that mounted into the hole in the shell. But this was a huge hassle and I had to make the hole bigger.
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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Have you tried looking at any of the wiring raychem offers? Pretty similar to the stock shimano stuff.
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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Gave you this link in another forum, but here it is too:

http://fairwheelbikes.com/...lit=di2+plug#p101918
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Re: Making your own Di2 connectors. Any tips? [pyrahna] [ In reply to ]
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Thanks for the tip. I am about to start a new di2 project to put di2 on a road bike and will look at the wire.
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Re: Making your own Di2 connectors. Any tips? [goodboyr] [ In reply to ]
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I do follow the Fairwheelsbike forum. I usually post to both. But I actually find this forum to generate more conversation then this or weightweenies or any of the other bike forums. Even on pure biking topics.

There are two really good threads that I used to learn when I got started and one of them was on here from, I think his name is, Locus.
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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You asked if anyone had made their own connectors for Di2 and to share that with you so I gave you the link that describes how someone else did it.
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Re: Making your own Di2 connectors. Any tips? [goodboyr] [ In reply to ]
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Sorry about that, I really, really appreciate the link. I have seen the thread you shared. The thread, you shared, is what made me start thinking about making my own. But I wanted to take a different approach only because I thought that I could make multiple more quickly and less human labor. Once I had the measurements I could just mount the plastic and center and with CNC the mill would take care of the rest. It is possible that I would not need to center each time. Then basically just a flip of the plastic.
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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you could spend hours on digikey.com. More connectors than you can shake a stick at.
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Re: Making your own Di2 connectors. Any tips? [corneliused] [ In reply to ]
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Sorry about the confusion. It is not that I want to connect my own wires is why I am doing this. I want to connect into the Shimano wiring without cutting their wires.
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Re: Making your own Di2 connectors. Any tips? [bartturner] [ In reply to ]
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Just for reference on this old post. The Copper leads in the connectors is 26awg and not 18 (you could probably use 28awg which should handle the amps and get thru close spaces easiest) and but certainly not 18awg. I have made my own small contact switches with the ECU's from big climbing switches from DI2 and the wires are again, not 18awg. That post will have people purchasing the wrong too large size wire for their extensions. Also, it is really easy (if you are a electronics or computer geek) to make your own extensions with the correct size wire. Just find advice on youtube about splicing small electronic wires.
Last edited by: g777: Mar 1, 24 6:06
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