When I built my frame and used internal routing. My instructor Doug Fattic wouldn't even let me use those generic braze ons where you run full housing through the top tube. Like this.


Instead he had me use a brass tube that went from one machined cable stop to another so no housing is ran internally. Just feed your cable and no messing around trying to fish it out the other side. Very clean and hassle free setup. Took a little longer to do well worth it in the end. Also I notice the paint on the edges of those are chipped from the housing moving around.

We still have to mess around with it at work as some new road frames run cables internally but no housing or guide tube. It's not that bad to setup but some bikes can be a royal PITA.