Got Brakes? (Part 1)

Let’s start with one concept and a few terms.

The brake is the thing that slows you down and stops you.  It does this by using friction to convert mechanical energy to heat energy.  One concept should be kept in mind.  Friction always means wear.  By their very nature, brakes cause something to wear away, and eventually to wear out.

The control that you grab to apply the brakes is the brake lever.

Modulation:  This is the ability to vary the brake force.  A brake should be able to be modulated from barely slowing the wheel to a full lock up.

Center Pull Caliper:  A type of brake found mostly on older road bikes.  There is a straddle cable between two brake arms.  The brake arms rotate on a common pivot, and cross each other to apply force to opposite sides of the rims.

Side Pull Dual Pivot Caliper:  This is the kind of brake found on most modern road bikes.

Cantilever:  You find these on older mountain bikes, on some touring bikes, and on many cyclocross bikes.  These consist of two independent brake arms, with a straddle cable running between them.  Each arm rotates around it’s own pivot.  The pivots are on the forks, or the seat stays, on opposite sides of the wheel.

Linear Pull:  The Shimano proprietary name for these is V-Brakes ™.  Two longer arms, each on its own pivot.  These have a stiff steel “noodle” leading the housing to one side, and a cable between them.

Disk Brakes:  Found on many modern mountain bikes, and some heavy duty road bikes.  A rotor, is a disk of steel, bolted to the center of the hub.  There is a caliper mounted on the frame.  The caliper contains one or two pistons, which move small, high friction pads against the caliper.

There are two basic types of disc brakes.  Mechanical Discs are operated by a brake cable just as the other brake types are.  Hydraulic Discs are not cable operated, but use some kind of brake fluid to operate them.

Drum Brakes:  This is a much less common type of brake.  It has a pair of brake shoes inside a housing, called a drum.  The shoes are move outward to press against the inner surface of the drum.  These are generally a mechanically actuated brake.

There are advantages and drawbacks to every one of these brake types. We’ll be discussing those aspects in some detail in the near future, and we’ll have some tips on maintenance.