Tuesday 24 March 2015

Bicycle Brakes


When you were young, and the rush when you first dared to ride your bike down that really steep hill in your neighbourhood? The ride down is great!. Stopping isn't always so much fun though, especially if you have left it a bit late. Bicycle control relies on two elements: steering and brakes. If either of these is missing, you are an out of control cyclist, hazardous to yourself and others.

The first bicycles ever invented didn’t have any brakes. Band-aids hadn't yet been invented, so the next logical step was to devise a stopping system. Thus, brakes were born to help riders slow down and stop, and bicycles suddenly became more popular, and dentists lost out on some business! By increasing frictional force on the wheels, cyclists were able to slow themselves down and stop.

The first widely used braking system was "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 shoe to press against the outer side of the tire. Of course, the friction created caused excess wear and tear on the tire, something of concern with early rubber compounds. 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 from not very much to even less!

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 stunts, but not so much for retaining control like this.

Today's mountain, road and stunt bikes use either caliper rim brakes or disc brakes. Caliper rim brakes operate by pulling a lever to tighten a cable. 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. On the other hand, modern disc brakes overcome the wet weather problem and provide strong reliable stopping in any weather due to their design.

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, so should be part of your regular basic bicycle maintenance routine. Your safety should not be overlooked, as its too late when you are under a bus wishing that you hadn't kept putting off some maintenance, or weren't sure if something was adjusted right. In fact, if it seems too daunting to do, take it to a shop, or get an online pro to guide you.

No comments:

Post a Comment