How to adjust bicycle brakes yourself
Brakes that feel soft, pull to one side, or rub constantly are one of the most common complaints we hear. Most of the time the fix is straightforward and doesn't require a trip to the shop. Here's how to work through the most common brake problems.
Rim brakes: the basics
If the lever travels more than halfway to the bar before the brake engages, the cable needs tightening. Most brake levers have a barrel adjuster. The small knurled cylinder where the cable enters the lever. Turn it counter-clockwise to take up slack. If the barrel adjuster is already wound out as far as it goes, you need to pull more cable through the pinch bolt at the caliper.
If the brake pads are hitting the tyre rather than the rim, loosen the pad fixing bolt, reposition the pad so it contacts the rim squarely, and re-tighten. The pad should hit the rim parallel to the braking surface, not angled up or down.
Mechanical disc brakes
Mechanical disc brakes have a fixed pad on one side and a moving pad on the other. The most common issue is the rotor rubbing against the fixed pad, which doesn't move when you release the lever. To fix this, loosen the caliper mounting bolts slightly, squeeze the brake lever to centre the caliper over the rotor, and re-tighten the bolts while holding the lever.
If the lever still feels soft after cable adjustment, check the cable housing for kinks or cracks. Compressed or damaged housing absorbs lever travel and makes the brake feel spongy regardless of how tight the cable is.
When the pads need replacing
Rim brake pads have wear indicators. Small grooves in the pad surface. When the grooves disappear, the pads are done. Disc brake pads should have at least 1mm of compound remaining. Worn disc pads make a metallic grinding sound and can score the rotor if left too long, which turns a $20 pad replacement into a $50-$80 rotor replacement as well.
If you've worked through these steps and the brakes still don't feel right, bring the bike in. Sometimes the issue is a stretched cable, a worn lever, or a rotor that needs truing. Things that are easier to diagnose in person.