Internal cables enter the frame in different ways. Some manufacturers use a small cable port, which barely has enough room for a cable outer.But more commonly, especially on newer bikes, there’ll be a fitment that houses the cable end, which can be removed.
The method in the video should work for either method.
How to thread internal brake and gear cables
Video: BikeRadar’s James Tennant explains how to thread internally-routed cables. This video is part of the Park Tool Maintenance Monday series. You can purchase the Park Tools used in the video at a number of dealers across the UK and internationally. For more maintenance videos, subscribe to the BikeRadar YouTube channel.
Tools for the job
Hex or torx keys
We’re using some thin piping to help route the new cable through the frame. New frames often come equipped with this, and it’s removed during the building process, so it’s worth asking your local bike shop if they have any spare.
If not, it’s also found in cable outers, and with a bit of perseverance you might be able to very carefully remove a section, using a blade and some needlenose pliers.
Snip the cable from the derailleur using a cable cutter – it’s important to use the right tool as you need a clean cut. You’ll want to snip above the cable retention bolt to avoid the frayed area. Leave the cable inner in place for now.
Remove any plastic ports from the frame then remove the cable outers and cable ends from the open end of the cable.
Place the thin plastic pipe on to the gear cable and feed it along until it reaches the other exit in the frame. It’s vital that this pipe stays in place, so tape both ends to the frame.
You can now remove the inner cable from the housing and shifter.
Fit the new inner cable to the shifter and cut a new length of outer cable if required. Thread the inner cable into the first piece of outer making sure the plastic end caps are fitted. Feed the new inner into the plastic pipe that is taped through the frame.
When it’s clear of the other end, you can untape the pipe and pull it off the inner gear cable.