Bike brakes 101
Your bicycle's brakes are its main safety feature. They help control your speed and stop when you are ready to stop. There are many types of bike brakes for different applications. They all have advantages and disadvantages depending on use. There are brakes designed best for road bikes and some that work best on a mountain bike. There are different styles of rim brakes that apply stopping power to the rim and different types of hub brakes that apply stopping power to the hub area of your wheel. We'll break all of this down for you in a way that is as easy as possible to understand.
Brakes are the component of the braking system that actuate the brake pads and directly apply stopping power to either the rim or the hub of a bicycle wheel.
Brake pads are pressed to the rim or disc to apply stopping power. They are made of many different compounds for different applications. Each style of brake has a specific style of pad that will work properly with that brake. Some pads have cross compatibility and can be used for multiple platforms, mainly cantilever and V-brakes. It is important to check brake pad wear and alignment to ensure safe riding.
Brake levers actuate the caliper and are normally located on the handlebars. They are the rider interface with the braking system. There are two main types of brake levers: those intended for drop bars and those designed for flat bars. From there, there are levers designed to work with the different variations of brake calipers and dual control levers that control braking and shifting. With dual control levers you have to determine the proper brake interface and shift interface.
Drop bar levers
Drop bar levers are ergonomic levers that mount to the front, curving section of a drop bar. They act as the main hand placement position on most road bikes. Drop levers are typically designed to work with center-pull or side-pull brakes. If you are using linear pull brakes with drop levers, you must use a lever that is designed to function with the increased mechanical advantage that linear pull brakes afford.
Flat bar levers
Flat bars have their own set of levers, typically called mountain bike levers or BMX levers. It is important to know which type of brake the lever will be used with. Center pull and side pull brakes use one type of lever, while linear pull brakes need a special lever.
Aero levers are special levers that attach to the end of bull-horn-style handlebars for time trial or triathlon use. They typically attach to the inside of the handlebar with an expansion nut.
Rim brakes apply stopping power (friction) to your wheel's rim. Rim brakes are generally actuated with a cable which is pulled with a brake lever mounted on the bike's handlebars. There are a few different ways in which the cable attaches to the brake. Another way to classify brakes is by mounting style. Most brake types crossover, so defining them can become confusing.
The manner in which a cable connects with and actuates a brake and brings the pads to the rim is a key characteristic to consider when shopping for the proper brake.
Center pull brakes have a split or "straddle cable" that connects to the two opposite brake arms and is pulled from the center to bring the pads to the rim.
Linear pull brakes use a cable stop to act as one anchor point, stopping the cable housing and anchoring the cable's end on the other brake arm. When the cable is pulled, the two arms are actuated and stopping power is applied to the rims.
Side pull brakes have a single cable running down the side of the caliper and work similarly to linear pull in that the housing and cable work together to actuate the brake arms. The big difference between linear pull and side pull is that side pull calipers have both brake arms on both sides of the caliper and pivot around the anchor bolt.
The manner in which a rim bike brake is attached to a bicycle frame and the way that the brake functions is the other key defining characteristic.
Cantilever brakes are characterized by two separate brake arms that pivot around two separate bolts mounted into the frame on opposite sides of the wheel. The two styles are standard cantilevers with bent arms and a center pull straddle cable, and Shimano's patented V-brake style with straight arms and a linear pull cable.
Shimano developed a straight arm cantilever brake that is actuated from a linear pulled cable. This V-brake systems offer more mechanical advantage than traditional cantilevers requiring a brake lever that applies less advantage.
A brake caliper mounts to the bicycle frame at a single, central point that also acts as a pivot point for the brake arms on both sides of the rim. Calipers can be actuated with a side pull or center pull.
Single pivot: In single pivot caliper brakes, both brake arms pivot around a single, central point that also anchors the caliper to the bicycle.
Dual pivot: Dual pivot brakes anchor and pivot around a central point with an additional pivot on one side that adds mechanical advantage. Dual pivot brakes are the norm in today's road cycling market and are generally lower profile and higher quality than single pivot brake calipers available today.
Hub bike brakes apply stopping power to your wheel's hub. Sometimes they are internal (drum and coaster brakes), and sometimes they are external (disc brakes). Internal hubs can be actuated via brake levers or by applying reverse torque on the crank arms. External hub brakes are generally actuated with a brake lever attached to the handlebars.
Disc bike brakes use a caliper attached to the bicycle's frame or fork that apply stopping power to a metal disc attached to the corresponding hub. Disc brakes do a much better job at dissipating heat than traditional rim brakes and, because they don't interface with the rim, don't cause any rim wear. They have become extremely widespread in off-road bikes and with tandems for these reasons. The main things to consider when purchasing disc brake parts are whether the brake is hydraulic or mechanical, the disc rotor diameter and interface, and the caliper mounting interface. There are adapters that can be used to aid in cross-compatibility, but not all brakes work with all bikes.
Drum brakes are actuated by a brake lever, generally mounted on the handlebars. The brake actuation presses brake pads against the inner wall of the hub shell. They are popular on tandems and motorized bikes. Since they are internal, they work well even in the worst weather conditions.
Coaster brakes work in a similar fashion to drum brakes. The large difference is actuation; while drum brakes are actuated via a brake lever, coaster brakes function with a reverse pedaling motion. Pedaling backwards forces a brake cone to push brake pads against the internal hub shell. Normal pedaling motion disengages the brake cane, allowing for normal pedaling. Coaster brakes are only installed on the rear wheel of a bicycle.