I just bought a used bike that has Ultegra di2 R8070 groupset. I noticed the seat post has some dirt so I removed to clean up. I carefully pushed the di2 cable down the tube. When reinserting, I noticed it was a bit hard to push down so I applied some force. Unfortunately, the cable got tangled between the tube and the post and it got severed. I took it out, inspected and saw it has 2 small cables (red & back). I cut them to expose the wires and hand tight them. But the whole system has no power.
I have never had a bike with electronic shifting before, I did something stupid, please help. It was shifting wonderfully before the cable was cut.
by dandaman1728
15 Comments
If you have a soldering iron and some shrink wrap tubing this is a pretty easy fix.
Since you had to ask this question I’m kind of assuming you don’t have this stuff.
Don’t splice this. Just buy a new cable. There will be a junction box nearby to connect to. They are usually not too hard to get to.
You can just disconnect the ends and buy a new cable. Probably the most reliable long term solution.
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One thing you can try after you join the wires is to trickle charge the unit, use a lower wattage charger like 0.5A one or something. This might reset the BMS.
One of the cells might be dead since lipo batteries usually come in 3.7V cells.
As others have said, don’t bother attempting any repair, these cables are not super expensive, just get a new one for the affected run. It would usually run to a junction box or one of the derailleurs and simply connects with a click. You want the model EW-SD50 with the correct length.
This post is out of hand.
Replace the cut wire. Soldering and bullshit is stupid. It’s a high end bike not a waffle maker from the thrift store.
Buy the shimano install tool if you want to be exact about it but really just unplug the two wires ends of the cut wire and replace with a new wire. Plug the damn system in to charge the battery.
If if still isn’t working go to a shop so they can plug into E-Tube and diagnose where the problem is.
Or just go to the shop in the first place and let them handle it.
Goodness. This is ridiculous. Get it together y’all
The cables are cheap. Just buy one
I did this also when I got my first bike with di2. Had to take my bike to LBS since I didn’t have tools for removing bottom bracket.
No problem, it’s wireless
Welcome to the severed floor
You now have SRAM. Get ready for chain drops
Buy a new cable, they are cheap
Once you’ve replaced the cable (get the plastic Shimano installed tool also, it’s the price of a tyre lever) you might need to plug it in to Etube and reset the battery (which contains the brains of the system). I had to do this when I accidentally disconnected my front mech on R6870 Di2.
New bike day /s
Buy a new cable