Question

how to remove the internal cables​

Answer 1

Answer:

Snip the cable from the derailleur end, leaving it as long as possible.

Release the cable housing from the bike by snipping zip ties. Take into consideration the frame and routing configuration of your bike. You will be removing the housing from inside the bike frame, while leaving the cable itself. This will help you guide the fresh housing through the frame. On our example bike, the cable is routed through the downtube.