Defective brake cables are obviously something to avoid. A snapped inner cable always happens unexpectedly and at the moment you need to slow down. To be safe, if your cables show signs of serious fraying or any rust, it’s probably time to fit new ones. So what are the danger signs and how do you keep your cables in tip-top condition? Here are some tips.
Outer cables are prone to damage where they enter the brake levers. If the plastic is split and you can see the metal underneath as in this photo, water can probably get in and may be causing hidden rust damage to the inner cable. Now is the time to get some new outer cables.
New outer cables are usually longer than you need. To cut these, first cut through the plastic sheathing right around the circumference of the cable to expose the spiral metal core.
Next, bend the outer cable over at the cut so that the metal spiral is forced open. The gap needs to be big enough to allow the jaws of your cutting tool to get between the spirals.
Use a pair of diagonal cutters or pliers to cut the cable. If you did the previous step correctly, cutting without crushing the outer should be a snip!
Inner cables lead a hard life especially where they enter the brake levers and where they are clamped in ‘pinch bolts’. Inner cables with broken strands need monitoring and ought to be replaced for safety and for easier maintenance. This picture shows signs of damage above an anchor bolt.
To weatherproof inner cables and to keep them working smoothly, always grease them before you thread them through the outer cable. To do this, use your finger and thumb to pull a dollop of grease along the entire length of the inner. Do this with all new cables and whenever you service old ones.
Frayed cable ends make cable servicing much more difficult: removing a frayed inner is easy, but refitting it can be nearly impossible.
One way to avoid frayed cable ends is to leave plenty of excess inner cable protruding past the anchor bolt. Then, if the end does begin to fray, it can be trimmed off. Also, a nice long inner cable is easier to get hold of while you are tightening the anchor bolt. Therefore, I prefer not to trim inner cables at all and simply coil the excess neatly as shown here.
Another way of preventing cable ends fraying is to put some epoxy glue (like Araldite ‘rapid’) on them as shown here. This literally sticks the individual metal strands together so that they cannot unravel. You can achieve a similar effect by soldering the ends of the inner.