Brake Dance

Mar 01, 2001 View Comments by

Brake Dance

For years drum brakes were the best way to slow your motorcycle down until a more effective system took over: the disc brake. Honda was the first manu­facturer to introduce this new brake system in series production. The legendary CB 750 Four (1969) was the first production bike incorporating a hydraulically operated disc brake at the front wheel. A few years later this system became standard in the motor­cycle industry due to hefty increases in motorcycle power and speed.

The concept and function of the disc brake illustrate the advantages of this system. The hand or foot lever activates a hydraulic piston in the master cylinder. This piston puts pressure on the brake fluid in the brake lines and this force is transferred to the piston(s) in the caliper at the bottom of the forks or the end of the swingarm. Then these pistons push the brake pad(s) toward the disc rotor mounted to the wheel. This procedure slows down the rotation of the wheel and you are braking.

Within this process the transferred forces show little wear and tear, which makes the system of a disc brake so desirable. Also, the weight of the disc brake system is lighter than a drum brake because of the small hub diameter and the thin rotor. This also reduces the un-sprung weight, which makes the adjustment for the suspension a lot easier. In the beginning of the disc brake age there was only one problem: When the rotors got wet in rainy conditions the stopping power decreased appallingly.

All the bikes with disc brakes suffered the same trouble and many cures were offered to get the pads to grip. Holes, grooves and slots appeared in all kinds of patterns but finally it was the special mixture of pad and rotor material that solved the problem at the end of the seventies.

The secret of a perfectly working disc brake is the arrangement of components, and the right mixture of them makes it work – as in a great cocktail. Vitally important are the correct ratios for the pistons in the master cylinder to those in the calipers. Along with the compounds of pad and rotor material, correctly sized rotors and other refinements make the difference between bad and good brakes. Rubber hydraulic lines are very common but can be changed to steel-braided Teflon brake lines to make the system more effective. These steel lines don’t have a tendency to extend like rubber lines. The transmission of the forces is improved and you can easily measure out your braking power.

Nevertheless, disc brakes also need some maintenance. Worn out pads and old brake fluids need to be replaced (see photos). If this job is done well, your disc brakes will work properly and show off their advantages while you’re dancing inside the curves.

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