Cable brakes work by using a cable to transmit force from the brake lever at the handlebars to the braking mechanism at the wheel, where friction is applied to slow down or stop the bicycle. The specific mechanics differ depending on whether the bike uses rim brakes or disc brakes.
Rim Brakes
- Lever Action: When you squeeze the brake lever, it pulls on the brake cable.
- Caliper Activation: The brake cable runs down to the brake caliper, which is mounted on the frame or fork near the wheel rim. The cable is connected to the caliper arms.
- Pad Engagement: Pulling the cable causes the caliper arms to move, bringing the brake pads into contact with the wheel rim.
- Friction and Deceleration: The friction between the brake pads and the rim slows down the wheel's rotation, causing the bike to decelerate.
- Release: When you release the brake lever, the cable tension is released, and the caliper arms spring back to their original position, disengaging the brake pads from the rim.
Disc Brakes
- Lever Action: Similar to rim brakes, squeezing the brake lever pulls on the brake cable.
- Actuation of Mechanism at Caliper: The cable connects to a mechanism, often a lever arm, on the brake caliper mounted near the wheel hub. This mechanism applies pressure to the brake pads.
- Piston Activation (Mechanical Disc Brakes): In mechanical disc brakes, the cable-actuated mechanism directly pushes one or both brake pads against the rotor.
- Pad Engagement: The brake pads press against a rotor (a metal disc) that is attached to the wheel hub.
- Friction and Deceleration: The friction between the brake pads and the rotor slows down the wheel's rotation.
- Release: Releasing the brake lever releases the cable tension, and the brake pads retract from the rotor.
Common Elements
Regardless of the specific type of cable brake, the fundamental principle involves converting the rider's hand force at the lever into a mechanical force that applies friction to the wheel, thereby slowing the bike down. Regular maintenance, including cable lubrication and pad replacement, is crucial for optimal performance.
