How Do Motorcycle Brakes Work?

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Most motorcycle brakes work like the disc brake system on a car. Some have a drum brake, but front- and rear-disc brake systems represent the vast majority of motorcycle brakes today.

Brake Configuration

The major difference in braking systems lies in how the brakes are triggered. On a car, the brake pedal triggers all of the brakes at once. On a motorcycle, there are a couple of options.

Most motorcycle brakes activate the two wheels independently, employing a lever on the right side of the handlebar to operate the front brake and a foot pedal on the right side for the rear brake. This separation allows the operator to engage the front brakes first (these carry about 70 percent of the braking load), which increases safety in most situations.

A second configuration engages both brakes with the handlebar lever, automatically delaying the onset of the rear brake for the operator. Riders debate whether this configuration actually offers a safer ride, but it is largely a matter of personal preference.

How Motorcycle Brakes Work

No matter which way motorcycle brakes are triggered, they operate the same: A cable or a lever engages the master cylinder, causing a piston to exert pressure on the brake fluid. Because brake fluid cannot be compressed, that pressure is conveyed through the brake lines to another piston in the brake caliper. The caliper then exerts pressure on the brake pads.

The resultant pinching of the brake pads brings them in contact with the rotor, which is attached to the wheel. The friction created between the rotor and the pads converts the kinetic energy of the motorcycle to heat, which slows the bike. Because motorcycle wheels are fully open to the environment, the rotors and the pads dissipate this heat efficiently.

Brake boosters are unnecessary in all but the heaviest models. Most riders can supply ample force for braking on the lighter mass of a motorcycle.

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A Note About Rotors

You’ll notice motorcycle brake rotors are rarely solid, smooth discs. The same open nature that helps air-cool the brakes also exposes them to water from the elements and wet roadways. Slots and cross-drilling increase safety by carrying water (and steam created through contact with hot rotors) away from the rotor where it can interfere with rotor/pad contact and brake efficiency.