MGOOF : Modern groupset on old frame

Cool project - however here’s some thoughts:

• the connecting plugs for EPS are about 7mm diam, which means at least an 8mm hole (larger probably as you won’t be able to use magnets to guide) at each entry/exit point on the frame. 8mm hole in a skinny steel chainstay 🤔
  
• the BB shell will need to house 2 EPS cables. These would be from the battery (seatpost), one to the RD, one going toward the headtube. It might be a squeeze fitting the cables around the cranks axle.
  
• EPS cable connections aren’t intended to be outside of the frame, so the stick on Di2 routing option I’d miss unless you are certain the bike won’t ever see a wet wash or rain
  
• IMO the best option would be checking with your frame builder to see whether the DS chainstay/BB shell can be replaced/amended to something larger to cater for internal routing. It would be such a nice build if this can be done 🫡