Originally Posted by
Le Mechanic
Mountain and gravel bikes with internal routing generally have full runs of housing, where road bikes usually have a cable stop with just the inner cables running through the frame. After you've replaced a few of them, it's really not any harder than replacing external cables, just a different process. I've seen a handful of the crossed over cable issue. It's fairly easy to recognize once you know what to look for. Another issue that's closely related and common with Specialized is the small teflon tubes used in the cable stops. I've seen many instances where the cables have been replaced and the cable stop or guide tubes were left out. What happens then is that the inner cable will actually "saw through" the aluminum cable stop causing damage and poor shifting. I made a video some time back with some demonstrations of both potential problems as well as general internal cable routing tips.
Yep, this Specialized has what I would call cable guides going into the frame, basically plastic cable stops that screw into the frame. I couldn't get the one for the front shifter off because the screw was so tight and I was stripping it so I had to resort to the string-and-vacuum method of pulling the cable thru. At that point I realized that the shifter wasn't pulling the cable and after spending so much time routing the cable I just took it to the LBS, which is where they saw the problem. This being my first time messing with internally routed cables (well second if you count the right shifter) I doubt I would've figured this one out quickly so I'm thankful that those guys had it back same day... because at some point I did actually want to be able to ride again.