Maintenance Monday: How to adjust road brakes
This entry was posted on May 12, 2014.
Most modern road bikes use caliper brakes. In the most common design -- dual-pivot, side-pull caliper brakes -- the braking cable enters the calipers from the top of one side of the mechanism. When the brakes are pulled, one arm pivots from the center and the other pivots from the side, forcing the brake pads into contact with the rim of the tire.
Caliper brakes provide good stopping power, light weight and simple operation. While they can be knocked out of alignment, adjustment is easy and straightforward. Let’s explore the adjust process now.
Time required: 20 minutes
Tools and supplies required:
- Allen wrench (aka hex wrench) set
- Rubbing alcohol
Step 1: The first step in adjusting your brakes is actually dealing with the rim. It is a good practice to clean your rims anytime you service your brakes. A clean rim surface allows powerful braking and reduces the risk of brake slippage or squealing. Use rubbing alcohol and a rag to clean the rims of both bicycle wheels. Remember to have good ventilation when using rubbing alcohol.
Step 2: Next, let’s make sure you don’t have to replace your brake pads. You can check them for wear and tear by crouching down in front of your bicycle and looking down at the brake pads from the top. There should be at least 1/2 inch (12mm) of rubber remaining on the pads. If the rubber is worn below this point, it is time to replace the pads. Luckily, brake pads are cheap and easy to install.
Step 3: Now let’s check the brake cable tension. Pull your brake levers on the handlebar and note the amount of spacing remaining between the lever and the handlebar when the brakes are fully engaged. There should be at least 1 inch (25mm) of space. If there is less space, let’s tighten the brake cable.
Step 4: Locate the location where the brake cable enters the caliper arm mechanism. There should be a small, grooved screw here that can be turned in either direction. This barrel adjuster can be turned counter-clockwise to tighten the brake cable or clockwise to loosen it. The cable tension can also be adjusted by releasing the bolt that holds the brake cable in place on the caliper mechanism and pulling the cable in to increase braking tension, or releasing the cable to decrease braking tension.
Step 5: Now we are ready to center the brake pads. First, find the bolt that mounts the brake calipers to the frame of the bicycle. Loosen the bolt using an allen wrench. Now, sighting along the wheel, move the brake caliper mount side to side until it is properly aligned. There should be equal spacing on either side of the wheel. Now retighten the bolt to lock the calipers in the correct position. Note that some caliper brakes have an adjustment screw on the top of the mount. In this case, turn this screw until the brake pad spacing is even.
Step 6: In order for the brake pads to operate correctly, they must be aligned on the horizontal axis. To do this, we must adjust each pad individually. Crouch down next to a brake pad and examine its alignment from the side. The pad should be parallel to the wheel so that, when the brakes are engaged, the pad contacts the rim of the wheel. If the pad is angled upwards or downwards, or if the pad will contact the tire or overlap the bottom edge of the rim when engaged, it must be adjusted.
Step 7: To adjust the pad orientation, loosen the bolt that attached the brake pad to the caliper arm. Align the pad correctly so that it contacts the wheel fully. Also take this opportunity to “toe-in” the brake pad. Tilt each pad slightly towards the forward portion of the bike, so when the brakes are pulled the front edge of the pads contact the rim slightly before the rear edge. This reduces the amount of noise made by your brakes and can increase stopping power.
Step 8: Repeat steps 4 and 5 with each brake pad, and enjoy the clean, powerful braking action!