First, shift your bike into the smallest gear and bring your barrel adjuster all the way in. Loosen the clamp on the derailleur, and remove your old cable. You’ll need to knock this cap off or cut the end to get it through. Up at the shifter you’ll need to find the access port, which is sometimes shielded with a cap. The cable should come out with a metal stop on the end.
Most of you are going to be changing your cable and your housing, so it would be a good idea to pick up a pair of cable cutters. You can use end nippers or dykes but, these are much easier.
You can use your old housing as a guide, but if you’re changing something else on the bike like your bars or your derailleur, you may need to dry fit it to determine the length. That’s what I’m doing. Here, I’m fitting it into the shifter, making a nice wide bend, and trying to match the length of the brake hose to keep things neat. As I run the cable, I’m keeping in mind that too long is better than too short. We can always go back and cut it more. Once I’m happy with the length, I can cut the housing and ONLY the housing. Don’t cut the cable until the very end.
To read the rest of the transcript, please turn on closed captions.
How to install a derailleur: https://youtu.be/BTYPHGWDE6E?list=PL5…
Fix wonky shifting: https://youtu.be/Kx3qcuvJxUs?list=PL5…
Third Hand (cable puller): http://amzn.to/2krEuXY