This Is Your...Shifter Cable

Change gears more smoothly with these three tips.

April 30, 2010

1. Making the connection

Cables connect the shifters on your handlebar to the front and rear derailleurs. When you deploy the shifter to move into a larger cog or chainring, you're essentially pulling on the cable, causing the front or rear derailleur to move, which shifts the chain. When the shifters release tension on the cable, the derailleurs move again and shift the chain to smaller cogs or chainrings. Cables run inside housings for part of their journey from the shifter to the derailleurs. What if you're able to shift into a bigger chainring with ease but you notice a delay moving into a smaller one? Usually the cause of that hesitation is a dry or dirty cable, which increases friction between the cable and its housing. Remove the cable and wipe it clean with a degreaser-soaked rag, then lubricate it with oil, such as TriFlow, using a fresh rag. Dribble a bit of oil inside the housing as well. If that doesn't do the trick, your cable is probably worn or stretched--problems you can't identify just by looking at it. It's best to replace both the cable and housing--it's not worth your time and trouble to install a spanking-new cable into gunked-up housing.



2. Fitting new cables

Before you fit a new cable to the front derailleur, shift the chain into the smallest chainring position. If you are fitting one to the rear derailleur, shift to the smallest cassette position. Remove the old cable by undoing the clamp bolt on the relevant derailleur and pushing the cable backward through all the housings and the shifter. Insert a new, lubricated cable into the shifter and back through all housings. Pull the cable though the cable clamp bolt on the front or rear derailleur, then, while still pulling on it, tighten the clamp bolt.


3. Cut Yourself Some Slack

No matter how new, clean or well-lubricated your cables are, you can't eliminate friction. But you can reduce it by shortening the length of unnecessary housing, such as those unwieldy loops between the shifters and that first cable guide on your frame. Though there's no exact science here, the golden rule is to have just enough housing that your handlebar can turn almost 90 degrees left or right. If it's too long, you'll experience excessive friction; too short and your cable could kink and bind inside the housing. After you figure out the proper length, cut your housing with a cable cutter and file any burrs that form at the ends. Use ferrules on each end to protect the housing.