Disc Brake/Drum Brake variant motorcycles

Editor@Throttle|Updated: March 5, 2018 12:42
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With the alarming rise in the number of accidents, safe riding is a major concern. Brakes play a major role in the safety system of a motorcycle. Motorcycle manufacturers, these days are launching bikes with front disc brakes as standard. But what exactly is the difference between disc brake variant and drum brake variant?

 

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To compare and contrast disc brakes and drum brakes, it is necessary to get an idea of the underlying principles involved. A brake is a retardation device which converts energy from one form to another. Here, the kinetic energy of the moving wheels is converted into heat energy by means of friction between the brake pad and contact surface. A brake’s efficiency is determined by its ability to convert kinetic energy to heat energy and also by the rate at which this heat is dissipated. Now, that key concept is understood, let us get to know the two brake systems. 
 
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What are drum brake variant motorcycles?

 
In drum brake variant motorcyes, the braking part is drum shaped wherein there are two large, curved brake pads inside the drum pushing outwards that slow you down. The main components of the drum brake are brake pads and piston.
 
 
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The vents provide quicker cooling making it easier to brake on mountaineous slopes. It is even easy to operate the brakes in wet conditions as they involve less braking effort. Since there are fewer parts and parts can be examined easily, it is easier to maintain them.
 
 
 

What are disk brake variant motorcycles?

 
Disc brakes have a rotating disc which rotates along with the wheel. Brake pads are present on both sides of the disc, which when pressed against the brake, forces the vehicle to come to a stop. When the brake pedal is applied, brake fluid pressure forces the piston to press the brake pads against the disc. Conversion of energy takes place and the vehicle comes to a stop. The Disc is usually provided with vent holes which allow heat to dissipate quickly. 
 
 
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The vents provide quicker coolng making it easier ro brake on mountaineous slopes. It is even easy to operate the brakes in wet conditions as they involve less braking effort. Since there are fewer parts and parts can be examined easily, it is easier to maintain them.
 
 
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Disc Brakes vs. Drum Brakes

 

In disc brake variants, vents present on the disc improve the heat dissipation rate. Also, they are exposed to air whereas the drums are not. In a vehicle equipped with drum brakes, excessive friction causes a surge in temperature due to which the drum expands outward. Because of this, more effort has to be exerted to bring the vehicle to a stop, since heat dissipation rate is directly proportional to efficiency of the brake. Another disadvantage of drum brakes is that they are pretty useless when exposed to water.

In a nutshell, Disc brakes are easier to inspect, have fewer parts, have a superior design and better stopping power. The only advantage Drum brakes have is that they are cheaper to manufacture.

 

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Conclusion - The Current Scenario

 

Most manufacturers, today are providing front disc brakes as standard in their new products. But most of the bikes continue to employ drum brakes at the rear. Is this a wrong thing?

The answer is no. As the years have gone by, drum brake technology has also improved so much that some of them are more efficient than disc brakes of yesteryear. Also, during braking, due to mass transfer, most braking effort is needed at the front wheels. Most of the entry level bikes do not require a rear disc brake. Using a disc will also increase the costs on all these bikes. Thus, although a front disc brake is absolutely necessary, a rear disc brake is not so critical.

So in modern motorcycles since maximum braking effort is required at the front, the front wheel is equipped with disc brake and the rear wheel with drum variant. This solves the necessary purpose and also reduces the cost considerably.

 

Image Source : BrakesNAutomotive