History’s first bicycles had no brakes. Over time brakes were born to help riders slow down / stop, and bicycles suddenly became more popular. By increasing frictional force on the wheels, cyclists were able to slow down and stop.
The first widely used braking system was called “the plunger”. It first appeared on the high-wheeled bicycles that were popular in the 1800s. The plunger operated on a simple principle. To slow down a bicycle, a lever was either pressed down or pulled up, causing a metal show to press against the outer side of the tire. Of course, the friction created caused excess wear and tear on the tire. Cyclists found that the plunger did not work well with pneumatic tires, even after covering the metal shoe with rubber. Wet surfaces were another drawback, as water decreased the friction between the brake shoe and tire, reducing the braking power.
The next major development in bicycle brakes was the “coaster brake”. Most of us have used coaster brakes, still popular in pint-size toddler bikes and tricycles. Some utility bicycles and cruisers also use coaster brakes. The concept behind coaster brakes is simple reverse motion. When the pedals are moved in a reverse direction, the brake mechanism inside the hub of the wheel pushes outward, creating friction and slowing down the bike. Coaster brakes are quite strong and tend to lock up and skid the rear wheel when engaged, so they’re great choices for sidewalk burnouts.
Most of today’s road bikes use caliper rim brakes. By pulling a lever, a cable is tightened. This cable then forces the brake pads or shoes to press against the inner rim of the wheel, stopping the bike. Caliper bicycle brakes are light and relatively inexpensive, but they do come with their own set of problems. Not hugely efficient on rainy days, wet brakes take twice as long to stop a bicycle because the water reduces friction between the brake and the wheel. Caliper brakes work best when pressure is applied gently.
Most of today mountain bikes use Hydraulic brakes. This braking system has transformed mountain biking because they enable us to go faster and stop harder. Disc brakes provide provide powerful and reliable braking in all types of weather and terrain. The principle behind any hydraulic system is simple: forces that are applied at the hand point are transmitted to the brakes by means of compressible fluid. As is common in hydraulics the initial force which is applied to operate the system is multiplied in the process. The amount of multiplication can be found by comparing the sizes of the pistons at either end. In braking systems for example, the piston driving the fluid is smaller than the pistons operating the brake pads therefore the force is multiplied helping you to brake easily and more efficiently.
Hydraulic brakes are even becoming popular on road bike because these brakes are efficient for all conditions.
It is important to balance the braking between the front and rear brakes while riding. If too much brake pressure is applied to the front wheel, your momentum and body inertia will take you right over the handlebars.
Over the decades, braking systems and materials have changed, but the fundamentals of slowing and stopping a bicycle have not. Bicycle brakes are still based on the concept of friction, and are still vitally important to your safety.