important: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.

How to Replace an Inner Brake Cable

Remove the old inner brake wire and install a new one.

Brake cable inner wires wear out over time. Other than obvious fraying, rust or visual wear, you can tell your cables are worn when your braking starts to feel sluggish. If lubricating the housings or brake levers doesn’t help, they’ll likely need replacing.

Tools

For this job, you’ll need a replacement brake cable inner wire. Most brake cables have a barrel end that looks like this, unless you have a road bike with drop handlebars, in which case it’ll have a cylindrical mushroom head like this. Often new brake cables will come with each type on both ends. I recommend stainless steel cables if you’re riding regularly in a wet climate, as they won’t rust. You’ll need a good set of wire cutters, some bicycle specific cable cutters if you’ll be replacing the outer cable housing, and some triflow or light lubricant. You’ll need either a 9 or 10mm metric open end wrench or a 5 or 6mm hex key for the brake’s cable pinch bolt. You’ll also need to know how to adjust your brakes and levers, as explained in previous tutorials depending on your type of brake system.

Brake Cable Removal

The first step is to carefully observe how your cable is presently routed from the lever to your brake. A misrouted cable can cause many problems. It may help to photograph each section of the cable from the lever to the brake so you can use it for reference. Your brake may not look like the one pictured here, but the concepts will be the same.

Now disconnect the cable by loosening the brake’s pinch bolt. Notice how the cable is flattened where it was pinched. I like to cut the cable just before this part so it is easier to remove by sliding through the outer cable housings. I recommend replacing the outer cable housings at the same time. See the tutorial titled “How to Replace Cable Housings”.

Brake Cable Installation

Once you have nothing but the brake lever and the cable left, line up the slots in the lever’s barrel adjuster and then pull the cable through and remove the head from the lever. Install the new cable into the lever the same way the old one came out.

Now turn your barrel adjuster clockwise almost all the way, so the barrel slots lock the new cable in place. Drop some light oil into your cable housings and make sure the outer housing’s cable ferrules are firmly in place before carefully sliding the new cable through the housing. Then route your cable the same way it was before and thread the inner cable under the pinch bolt’s washer. Pull the cable tight and tighten the pinch bolt. The cable will flatten when tightened. Always tighten bolts to the manufacturer’s torque specifications. Adjust the brake as needed. Search the other tutorials for your specific type of brakes.

Once installed and adjusted, cut the wire about 2 inches further along the cable. Your new cable should have come with a cable end that can be gently crimped on using wire cutters or pliers. This will prevent fraying. Then give the cable a slight bend and tuck it out of the way behind the brake arm.

Alex Ramon

A bicycle geek since early childhood, spent his twenties as a mechanic in bike shops. His passions include flatland BMX, unicycles, cycle touring, mountain biking and road riding.

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