Types of Brake Systems and Their Components
Cars have changed considerably as technology progresses. Often there is a blending of old and new systems, being the byproduct of change and innovation while not abandoning older methods of doing things. Some of these more notable changes can be seen in the structure of brake systems and the types of brakes assigned to all four wheels of a car. More information concerning parts of brake systems and how they interact can be found in our definitive guide.
Hydraulic brakes are the most common brake circuit in modern cars that utilize hydraulic (fluid) pressure to stop wheels in motion. The system uses two fluid-filled pistons and springs, one above the other. The ‘master’ piston contains most of the fluid and a pushing object. When the brake pad is pressed, the pushing object forces fluid into two’ slave pistons’, which are pushed together against the rotor (brake disc) to create the friction needed to stop a vehicle.
Frictional brakes are a traditional braking system that relies on the mechanical force to stop vehicles. The disk is surrounded by a calliper, which stores brake pads which are connected to the brake pad via a mechanism. The pads contract or expand based on the pressure or lack of pressure on the brake pad.
This is a new braking system that uses electricity powered by a motor to engage electromagnetic force to press brake pads together. Electromagnetic brakes in modern/hybrid cars provide instant stopping power since it is connected to an electric motor. The benefit of the electric motor is the lack of an intricate/mechanical system.
Additionally, the car provides an instant charge/reaction. The motor is integral to the vehicle and thus is regenerated and powered periodically, especially in electric vehicles.
Another significant part of the braking systems in cars is the actual type of brake being used to apply force.
Disc brakes are pure because they are made up of a singular disc spinning within the wheel. This disc is called the ‘rotor’ typically made out of grey iron or a combination of other alloys in some circumstances. Once the calliper mechanism is activated, the brake pads are squeezed against the rotor, creating immense friction. The resulting grinding can significantly wear away both the pads and rotor, usually leaving fine dust behind as a result of the transfer of energy.
Drum brakes operate similarly to the disc brakes. However, their structure is much different. Drum brakes are named drum brakes because of their distinct hollow, cylindrical shape resembling a drum. Brake pads line the inner rim of the structure and follow the motion of the wheel. When activated, the pads expand against the rotating sides of the drum, which eventually slows the vehicle down through friction.
Brake pads are the material pressed against the car rotor/ drum to create the friction needed to stop a vehicle. These pads are meant to be ground down into fine dust over time, though their material changes depending on the pad’s quality. More detailed information regarding brake pad materials is available in other blog posts.
Most common types of brake systems are hydraulic and electric.
Do Cars Brake with All Four Wheels?
Most cars have four brakes to be utilized, though they are not made equal, usually different designs. Typically, cars are set up with two ‘disc-brakes’ for the front wheels, while back-facing wheels utilize the lower performance drum brakes. This difference is intentional. The energy required to stop a vehicle is concentrated in the front due to back wheels throwing the most potential energy to the front. Disc brakes are proven to respond/ brake faster than drum brakes, which explains why they are preferred.
The same law applies to bikes, which can be illustrated by what happens if the front brake is pressed at a high velocity. The resulting force is enough to cause the bike to ‘buck’ the rider and send them flying, which is why it is not recommended. Though it is one extreme example of the difference between brake strength, it still follows similar principles.
Which Brakes are the Most Important
Following the previous line, front-facing brakes are considered the ‘more important’ part of the brake system. This is due to them handling the brunt of kinetic energy created by the vehicle stop.
Despite this, back-facing brakes still have an essential function, perhaps equally as important as being able to stop a car. Back-brakes in vehicles (just like in the bike example) extend the braking system’s life by sharing and distributing the workload. Without back brakes, the disc brakes at the front of the vehicle would endure much more pressure and be liable to fade much quicker than usual. Besides, back-facing brakes provide a safety mechanism as emergency brakes that last longer if the front brakes do end up wearing away.
Further, the less strained back-brakes provide steady control over a vehicle, lessening the chance of fishtailing or swerving.
Which Brakes Fade Faster, and How Fast?
Brake fade is inevitable. However, the rate at which they degenerate depends entirely on driving habits and vehicle weight. Generally speaking, front-facing disc brakes are more likely to fade due to the amount and frequency of friction they encounter. Even though drum brakes are more likely to fade in terms of actual wear-and-tear, their positioning at the rear of a vehicle prolongs their life span.