Quick Question: How Can I Keep the Derailleur Cable Ferrule From Falling Off?


Our most recent reader-submitted tech question is as old as shift and brake cables themselves. “The little ferrule on the end of my derailleur cable is always slipping off. Do I need a special tool to get a tight crimp, or is there a secret technique I’m missing?”

A ferrule, or cable-end, is used to keep derailleur and dropper cables from fraying at their cut ends. While frayed cable ends often function just fine, it’s nice to be able to remove the cable and reinstall it if necessary, and a clean terminus also looks better than a steel pig sty at the end of the line. Additionally, frayed cable ends on a dropper-post remote can puncture skin which is certainly worth preventing.

There are multiple methods to crimp ferrules on cabled ends, though there doesn’t seem to be an agreed-upon standard for how to tighten the little aluminum cap in place. A common crimping method is to put two sharp dents in the ferrule with a pair of cable cutters, being careful not to cut through the cable itself. Alternatively, a lot of folks use a pair of needle-nose pliers to cinch the cylinder down, or a dedicated crimping tool designed for electrical work. Whatever the instrument of choice, it’s important to give the ferrule a healthy tug to make sure it’s tight enough.

In addition to keeping ferrules in place, we’d love to hear your alternative cable tidying tricks. Some classics that omit the ferrule are to drop a dab of super glue on the end just after cutting, or a similar spot of soldering wire, a slathering of fingernail polish, or a hunk of heat shrink tube designed to encase narrow electrical wires. Many of these alternate methods can be removed or slid through the narrow cable passages of a derailleur without fraying when working on the bike.

I once worked at a bike shop where our lead mechanic would cut cables to length and then take them outside and spark the loose ends on the terminals of a car battery to fuse the small wires together. Quite the clever cat.

Your turn! Please share your cable tip tidying tips in the comments below.

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