If someone is considering doing this trick, I posted a kit ready to go in the classifieds.

FS: kit / Hack for TT Shimano 12 speed > manual FD shifting (extra shifters)


Kit is ready to go:
- Assembled
- Firmware updated on the satellite shifters - they are now recognized by Shimano 12-speed groupsets (they did not out of the box)
- Satellite shifters cable length extended (they are VERY short) via splicing (soldering) longer wires; Now ~700+ mm long
- Just need to unplug one of the existing Di2 wires upfront and put in the open port of this kit (green arrow), then link the short cable provided (red arrow) to the port that was freed up. Then connect your Shimano App to assign/modify functions to the shifters.
Fitted and tested to work.


I just changed my mind once all the work was done (typical me).


Shifters have been slightly modified to reduce their footprint and fit better in tight spots.
Installation via double sided-tape. I provide alcohol swipe to prepare the surface and extra lengths of the special 3M tape. More details and pics in the classified post.






Could be installed in different spots, this is one of them; I just test fitted, I never routed the cable inside the base bar.

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T. Guertin / Spocket