Shift Cable Replacement: Trigger Shifters
Shift cables can with time and use become worn, frayed, rusty or dirty, causing drag and resistance as it moves through the housing. This article will outline the process of installing and routing new shift cable into trigger shifters.
While many models and brands are reviewed here, your exact model of lever may be missing. In these cases you may be able to determine the replacement process by inspecting the lever and working carefully to access, remove and replace the cable based on some of the other examples here. If you are still having trouble contact the component manufacturer.
In mechanical shifting systems, the cable pulls or releases a set amount of cable to cause the derailleur to move a set amount. If the cable or housing has become kinked, worn, frayed or corroded, you may experience slow shifting, inconsistent shifting, hard shifting or no shifting at all. Replacing your cables and/or housing can improve shifting performance.
When replacing shift cables, it can a good idea to also replace the housing. See How to Size and Install Shift Cable Housing for replacement of housing, otherwise this article will cover only the cable replacement process.
Begin by shifting to the smallest cog in the front and rear. using the small release lever while pedaling to release as much cable as possible. This will leave your chain resting on the smallest sprocket in both the front and rear. Some Shimano front shifters have a 2x/3x selection switch. Set this to 3x and pull the release lever once more.
Now loosen the anchor bolt at the derailleur. If the cable is kinked or frayed, it is best to cut the cable ahead of the cable end cap or kink to allow it to move more freely through the housing.
Pull the housing away from the shifter. This will expose the cable for easier removal.
From here, the process varies slightly by brand:
Some shifters need to be partially disassembled to gain access to the head of the cable. This Shimano model features a plastic plug that unthreads from the shifter with a cross tip screwdriver, allowing the head to exit.
Some Shimano shifters — typically shifter/brake combos — have covers on the top. Loosen the screws and lift the cover off. Once you have the cover off, you may need a pick or small screwdriver to coax the head out of its retainer.
Pull the cable from the shifter. Install the new cable and pull on it firmly to seat it, and replace the cover.
Some shifters feature an open cable access hole, allowing the cable to be pushed right out. It may also be hidden behind a rubber cover. If there is no apparent access hole, it may be necessary to remove the top cover of the shifter. To remove it, it may be easiest to fully remove the shifter from the handlebar, then remove the cover.
Take note of the cable routing, then remove the cable — this sometimes requires prying the cable head out from under the spring with a pick.
Reinstall the cable by reversing the process. Give the spring a lift and it will seat nicely into place with a firm pull. Replace the cover.
There are other trigger shifters that aren’t Shimano or SRAM that have similarities to how the cable is accessed and removed. If your particular brand or model isn’t represented here, reexamine the shifter and look for cable access methods like the examples we’ve shown.
If you are replacing housing, this would be the time to do it.
To install a new cable in all of these shifters, it helps to sight the hole. You can typically see a little bit of light through the hole, but in a lot of cases it helps to use a flashlight.
Route the cable through the housing all the way back to the derailleur. Feed the cable through the groove of the pinch mechanism and pull the slack from the cable. Secure the pinch bolt screw (typically a torque spec of about 5 Nm). Cut the cable approximately 30 mm long and install an end cap. Finally, adjust limit settings and indexing.