Two of my handlebars are carbon and the brake cables & housings feed through the handlebars - so unwrapping everything and then fishing the housing through the carbon is a pain in the neck. I haven't really had problems deciding on the length - but I do tend to err on the side of too long vs. too short. I knew I was planning on switching handlebars on my surly to a much more upright & sweptback version than the flat bars that I started off with - so the housings were cut ridiculously long, which worked fine once I actually switched the handlebars.


If you have any empty ball point pens, you can cut the tubing where the ink is on the inside and sort of melt those over the ends of the cable to crimp off the cable ends. (Okay, between the duct tape and the ball point pen pieces, sometimes my bikes look a little bit less polished than they could)