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How to replace road bike shifter cables

Joseph Delves
13 Apr 2020

Shifting feeling sluggish? Odds are your cables are the culprit, so read our guide on how to replace them.

There’s not a pro rider or mechanic in the world who wouldn’t swap a top-of-the-line groupset connected up with grotty, old cables for an entry-level equivalent with fresh, snappy ones. Constant use and exposure to the elements means that the lines joining shifters and derailleurs will eventually deteriorate and start to affect your shifting performance – the most common symptom being a reluctance to shift downwards, as your derailleur springs start to lose the battle against increased friction.

While a quick squirt of lubricant can often freshen them up, once they start to feel gritty it’s time to swap both inner and outer parts.

Although internally routed cables can prove tricky to replace, if your lines run alongside the frame, swapping them isn’t a tricky job. Just make sure you have the right tools, then follow our eight-step guide and get stuck in.

How to replace road bike shifter cables

Step 1: Prep the bike and cut the old cables

Shift onto the smallest sprocket or chainring. Using cable cutters, chop the end caps off the cables. Undo the anchor bolts on your derailleurs.

The front sections of outer cable run under the bartape, so you’ll need unwrap this to get at them. Roll the brake hood forward and carefully unwind until just below the levers. Cut the electrical tape holding the outer cabling in place.

Step 2: Strip the outer and eject the inner 

Now disconnect the outer housing from the frame stops and remove it. Next remove the inner from the shifter. Gear cables usually thread in from the side. Push the cable backwards towards the lever.

The shifter will need to be selecting the highest gear and the lever pulled back to the bar for the cable to be released. 

Step 3: Measure up and cut

Cut your new cable outers to match the length of the ones you just removed. You’ll need to use dedicated cutters to get a clean finish – it’s important to get the ends as flat as possible.

Once cut, if the liner inside the cable seems to be closed off, use a pointed instrument like a pick to open it out again. Push the ferrules onto the ends of the cables. 

4. Fit the new inner cable 

Still in the highest gear, fit the new gear cable by sliding it gently into the lever at the same point that the old cable exited. The end should pop out the other side, although it may require a little wiggling.

Pull the end tight and click the shifter to make sure it’s correctly engaged. You should feel the tension increase as the shifter ratchets up. 

Step 5: Slide the outer cabling into place 

Slide the outer cable over the inner wire. Thread the wire through the frame stops and slot the ferrules on the outer section into place. Tape the first section to the bars.

You’ll need to slide the cable through the guide under the bottom bracket. That’s it for the front but the rear will need the last section fitting between the final stop and the rear derailleur.

Step 6: Attach to the derailleur and tension 

Pull the cable tight and attach to the derailleur. Now, without pedalling, shift the lever several times as if to change into a bigger sprocket or chainring.

This will put tension on the cable and help it settle into place, meaning your gears are less likely to go out of adjustment later. The procedure is the same for both front and rear derailleurs.

Step 7: Dial it all in

Ensure the barrel adjuster is dialed in. Undo the cables at the derailleur and pull them taut again to remove any slack that’s developed before refixing.

Chop off the excess cable and crimp on an end cap. If you’ve not touched the derailleur, all that should be necessary is to make some small adjustment using the barrel adjuster to re-index the gears.

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