How to Adjust Bike Brakes

Adjusting Your Brake Pads

Check your brake pads before you make any adjustments. The brake pads are the pads that clamp down on the front tire of your bike when you pull the brake lever. If the brake pads are worn down past the line labeled “wear line,” you’ll need to replace them before you make adjustments to your brakes. If the wear lines on your brake pads aren't labeled, they should be marked by grooves on the side of the pads instead. You can order new brake pads online or pick some up at your local bike shop. Make sure your wheel lines up correctly in the dropouts as well, or else it won't make good contact with your brakes.

Squeeze the brake lever to see where the pads hit the rim. Both brake pads should be coming into contact with the rim of the front tire at the same time. They should be hitting the center of the rim, with an equal amount of space above and below the pad. If the pads are hitting the rim too high or low, they could come into contact with the rubber part of the tire or the spokes on the bike. Crouch down to get a good look at the brake pads as you're squeezing the brake lever. If your bike has a quick-release mechanism, check that it isn't loose or hasn't come undone. Otherwise, your brakes won't squeeze tightly on the wheel.

Use an Allen wrench to loosen the bolts holding the brake pads in place. Turn the Allen wrench counterclockwise to loosen the bolts. Don’t loosen the bolts all the way or the brake pads will come out of the brake pad holder.

Move the brake pads up or down in the brake pad holder. They should easily move up and down once the bolts are loosened. If the pads were too low on the rim, move them up until they’re centered. If the pads were too high on the rim, move them down until they’re centered.

Re-tighten the brake pad bolts with the Allen wrench. Keep turning the Allen wrench clockwise until the bolts are fully tightened. Check to make sure the brake pads are centered. Readjust if needed.

Tightening Your Brake Cables

Test the tightness of your cables by pulling each brake lever. When you pull the brake levers, they should be about 1 ½ inches (3.8 cm) away from the grip on the handlebars. If the levers hit the handlebars when you pull them, the brake cables are too loose.

Loosen the barrel adjusters for minor brake cable adjustments. If your brake cables are just slightly loose, loosening the barrel adjusters might fix the problem. The barrel adjusters are located where the brake cables meet the brake levers. Loosen the barrel adjuster attached to the loose brake cable by turning it counterclockwise. Loosening the barrel adjuster will actually slightly tighten the brake cable. After you loosen the barrel adjuster, pull the brake lever to see if it fixed the problem. If the brake cable is still too loose, you’ll need to adjust it on the caliper. Leave the barrel adjuster as it is. Don’t tighten it yet.

Unscrew the bolt holding the brake cable on the caliper. The caliper is the main frame of the brakes that the brake pads are attached to. The brake cable is the thin cable extending off the caliper. Locate the bolt that’s holding the brake cable. Use an Allen wrench to turn it counterclockwise a few times until the bolt is slightly loose. Don’t unscrew the bolt all the way. Just rotate the Allen wrench counterclockwise 2-3 times until the bolt is loose.

Pull the brake cable outward to tighten it. Now that the bolt is loosened, you shouldn’t have any problem pulling the cable. Hold it in place with your fingers once you’ve pulled it taut. As you pull the cable, the brake pads should tighten on the rim of the front tire. You want them to be tight enough that there’s some resistance when you turn the tire, but not so tight that the tire isn’t able to turn at all. If you can't turn the tire at all, pull less hard on the brake cable so it's not as tight.

Tighten the bolt holding the brake cable on the caliper. Use the Allen wrench and turn it clockwise 2-3 times until it won’t turn anymore. The cable should be secure in place once the bolt is tightened.

Tighten the barrel adjusters on the handlebars. Turn the barrel adjusters you loosened before clockwise several times until they’re fully tightened. Tightening the barrel adjusters will loosen the brake pads that are clamped onto the front tire. Once the barrel adjusters are tightened, your brake cables should be all set! Test the brake cables again by pulling the brake levers. When you pull the levers now, there should be 1 ½ inches (3.8 cm) between the lever and the grip on the handlebars.