If your brake lever feels spongy, sticks halfway, or you have to squeeze it almost to the bar before anything happens, a worn or frayed brake cable is usually the culprit. This is one of the most common home repairs in cycling — and one of the most beginner-friendly, once you've done it once. Budget about 20-30 minutes per brake the first time through.
This guide covers mechanical rim and disc brakes using standard cable housing. If you have hydraulic brakes, this isn't your fix — those use fluid, not cable, and need a different process (bleeding).
Cables stretch and fray with use, especially if you ride in wet or gritty conditions. Most manufacturers recommend replacing cables every 1-2 years for regular riders, sooner if you notice any of the signs above.
Loosen the pinch bolt at the brake caliper (the bolt that clamps the cable in place) with your hex wrench. Don't remove it — just loosen enough to slide the cable free. If your brakes have a quick-release lever (common on rim brakes), flip that open first to give yourself slack.
Trace the cable back to the lever. There's usually a small barrel-shaped nipple that seats into a slot inside the lever body. Pull the cable through from the caliper end, and the nipple should pop free from the lever once there's no more tension on it. Set the old cable aside — you can use it as a length reference for cutting the new one.
Slide the housing sections off the frame. Check the ends — if they're mashed down, rusted, or the liner inside looks cracked, replace them. If you're doing a full kit, just swap everything.
Thread the new cable's nipple into the lever's cable slot exactly the way the old one sat. Pull it snug so the nipple seats fully — it should feel like it "clicks" into its pocket.
Feed the cable through each housing segment in order, following the same routing as before (photos before you started really pay off here). Make sure each housing end seats fully into its cable stop on the frame — a housing end that's not seated will cause mushy, inconsistent braking no matter how well you do everything else.
Pull the cable through the pinch bolt at the caliper by hand, taking up slack until the brake pads sit close to the rim or rotor — a couple millimeters of clearance on each side is the target. Hold that tension and tighten the pinch bolt. This is the step most people get wrong on the first try, so check the lever feel before moving on: it should engage firmly within the first third of its pull.
Cut the excess cable about 3-4 cm past the pinch bolt with your cable cutters. Crimp an end cap onto the fresh-cut end with pliers — this is a small step but it matters. An uncapped cable end will fray within weeks and eventually jab you or catch on something.
Squeeze the lever hard several times to seat everything, then recheck tension — cables often settle slightly after the first few pulls. Spin the wheel and make sure the pads aren't rubbing when the brake is released. Adjust the barrel adjuster (the knurled dial near the lever or caliper) for fine-tuning rather than re-doing the whole cable pull.
If your bike has hydraulic brakes, internally routed cables that snake through the frame, or you're dealing with a cable that's seized inside the housing and won't budge, it's probably worth the shop fee rather than fighting it for two hours. Everything else above is well within reach for a first-timer with basic tools.
Got a squeal or rub that won't go away even after a fresh cable? That's usually a pad alignment or wheel-truing issue, not a cable problem — worth a separate post.