Drum & Disc Brakes Advantages and Disadvantages Explained Disc Brake Ideal Options

Why are drum brakes being replaced by disc brakes?

Drum brakes advantages and disadvantages and suitable models, the advantages of disc brakes are "non-objective disadvantages" explained. The debate about which is better, drum brakes or disc brakes, has been going on for years, but it's a completely unnecessary one. Drum brakes are mainly used for "light, medium and heavy-duty - passenger vans", while disc brakes are used for small and micro passenger vehicles (≤ 6 meters in length - cars with less than 9 passengers).

Different models use different braking systems, so what's the point of discussing the two camps? As for the very few use "front disk rear drum" of the simple vehicle, such as Jetta Santana Tundra, etc., these cars have the value of discussion? Let's get to the point.

Drum brake features

Drum brakes + air brakes are a standard combination of passenger vehicles, the exact definition should be "drum brakes", air brakes refers to the use of compressed air to drive the brake and provide braking power system. So what are the advantages of drum brakes?

The contact surface between the brake shoe and drum is large, and the braking pressure is strong enough. The point: low manufacturing costs! Drum brakes have two sets of brake shoes, which can of course be called brake pads.

Automobile deceleration is the use of the brake shoes can not be moved, and with the rotation of the wheel drum friction deceleration; the nature of the friction refers to the mutual movement of molecules on the surface of the object (collision), which can not be activated by a group of directional force will be generated.

The moving car relies on the interaction between the road surface, which cannot be moved, and the rotating wheels; and the brakes are precisely the "drag force" that produces deceleration of the brake drums with the fixed brake shoes. The larger the contact surface and the greater the pressure, the more ideal the deceleration effect will naturally be. The advantage of drum brakes is that under the action of high air pressure, a very large contact surface allows the bulky body to slow down normally.

Disadvantage 1: The braking process of drum brakes is not linear enough, because after the elastic structure supports the brake shoes, the friction between the two will cause a slight movement, which will appear as a natural "bonded feeling of tension". The so-called drum brakes are a significant deceleration of the brakes when the pedal is lightly pressed, which is a disadvantage for passenger cars that require precise handling.

To put it plainly, the amount of braking force you want to output when maneuvering a small car depends on your foot, while with drum brakes, it depends on "your foot + the brake itself". All of these braking systems that don't feel good enough for your foot are basically not used in regular family cars, but that's still the point.

Disadvantage 2: The brake drum of a drum brake is also known as a "brake pan", and is shaped like a "pan" that sits inside the wheel hub. During braking, the brake shoe rubs against the inner wall of the drum, and the friction generates heat; under the action of the high pressure of the air brake and the very large contact surface, the drum brake will generate quite a lot of heat energy when decelerating, causing the drum to heat up.

The increase in temperature of the object reduces the surface hardness to a certain extent, and once the rigidity reaches the threshold, structural changes will occur during braking; it is still hard to detect, but it is true, and the result is a loss of friction that leads to brake failure. However, the high temperature of the brake drums comes from the inside, and the heat cannot be effectively reduced through the air, so this system is very prone to brake failure, and the average family car user does not have the ability to deal with emergencies, which is the reason why drum brakes are used in professional vehicles and by professional drivers.

Disc brake features

Disc brake + oil-activated is the standard for small microbus, oil-activated power is the use of negative pressure generated by the engine operation to achieve power, the pressure is generally lower. However, disc brakes are also able to use pneumatic power, just this kind of relatively high standard of gray cast iron manufacturing brake disc cost is high; need to strictly control the manufacturing cost of passenger and freight vehicles is not quite able to accept it, but there are also a few high-end tractor head use disc brake oh.

The point is: the disadvantages of drum brakes - disc brakes do not exist! For example, the use of brake fluid transmission braking force will be very linear, brake pads and brake discs do not have drum brakes "automatic force" phenomenon, so in the control process will be very fine. This state of driving allows for greater control of the body during extreme maneuvering, which is a very important quality for a family car that is more capable of acceleration and deceleration.

The second major advantage of disc brakes is that the disc pistons (pumps) are exposed to the air, and the chassis is designed to direct airflow across the brakes. The result is that the brakes are less prone to high temperatures over long periods of time, and effective air cooling is a guarantee of safe driving for amateur drivers.

At the same time, some vehicles use "perforated ventilated discs", which dissipate heat both inside and out, and some mid-range and high-end cars don't offer the option of M-gear precisely because the braking system is high enough not to require engine braking to assist deceleration.