I would like to upgrade a carbon fiber bike (Scott CR1) to Ultegra Di2 with internal wiring. Can I drill a hole where the cable holders are located (one next to the fork, one near the bottom crank & one at the rear, close to the derailleur) in order to route the cables inside ?

  • 2
    Consult a carbon-frame repair specialist and ask for a quote. Compare that quote to the cost of a new frame. Don't do it yourself. – Criggie Sep 21 '16 at 19:49
  • Preferably make arrangements with a funeral undertaker before taking the bicycle to the road. – Carel Sep 21 '16 at 20:10
  • I'm sure you can drill the hole -- carbon is not very hard. The question is whether doing so will precipitate a crack. – Daniel R Hicks Sep 21 '16 at 21:39
  • If you really want to ad electric shifting to your CR1 which has externally routed cables why not opt for the SRAM group that is wireless instead of wanting to drill your frame? (I'm not affiliated to the company and do not get money from them!) – Carel Sep 24 '16 at 19:45

This is one of those questions where if you have to ask "should I do this?", the answer is "no". Carbon frames need to be specially reinforced (during manufacturing) in the areas that drilling takes place see, for example, this discussion, and you could create stress concentration points or otherwise compromise the integrity of your frame.

The words "catastrophic frame failure" are not ones that you want to hear, particularly from your hospital bed.

| improve this answer | |
  • 1
    Probably if one understood the technology one could reinforce the area of the hole somehow, but it would take knowledge that isn't commonly available. (It would be interesting if one of the bike mags would study what you can get away with in this area, however. Likely carbon frames are not quite as sensitive to such modifications as one would be led to believe.) – Daniel R Hicks Sep 21 '16 at 21:42
  • @DanielRHicks the problem is that some of the reinforcing would need to go inside the frame, because you'd be cutting longitudinal fibres that need to go inside the outer wrapping layers. Well, you could put woven cloth around the whole tube for the full length, but that would get messy and heavy very quickly. And the aerodynamics would suffer. You might also find the frames are built to take the wiring, and this one isn't... eg, no hole between the chain stay and the down tube means you can't run a wire there without even more drilling. – Nuі Oct 3 '16 at 0:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.