What distinguishes front brakes from rear brakes? Both the front and rear brakes are located on the vehicle’s undercarriage. Isn’t that everything you need to know? At the most fundamental level, something could be “right,” but it would be completely deceiving. Friction and heat are the two most important factors to consider when comparing front and rear brakes.
According to the laws of physics, your car’s brakes are engineered to transform the kinetic energy of your moving vehicle into thermal energy through the process of friction. What finally stops your vehicle is the end product of that energy conversion. Then, the brakes and other parts of the car work together to release that heat into the air.
Here we reach the point of significant variation: the quantity of heat produced. Upon comparing the front and rear brakes, particularly the dimensions and mass of the brake rotors, calipers, and pads, it becomes apparent that the front brakes are significantly heavier, allowing them to withstand more pressure.
Different types of Brakes?
Brakes used in automobiles may withstand extreme pressures and temperatures.
While you brake, they transform the kinetic energy in your foot into thermal energy.
Having said that, the braking force isn’t evenly distributed among the four wheels. As a rule, the front axle is much more stressed than the back.
So, keeping that in mind, you can categorize the typical car brake according to its type and then its position.
The duties of the job are defined by the role itself:
- Rear brakes
- Front brakes
How it does its tasks is defined by its type:
- Disc brakes
- Drum brakes
FRONT BRAKE DESIGN
Take a step back to the physical world for a second to grasp the rationale behind the front brakes’ increased heat tolerance. Stopping suddenly causes the vehicle’s center of gravity to go forward, which in turn increases the load and speed transmitted to the front tires. Thus, the front tires get a greater grip, allowing for a greater amount of braking power to bring the car to a stop. With hard braking, the front brakes can reach temperatures of above 500°F, which is significantly higher than the rest of the car because they produce up to 75% of the stopping power.
Because of this, a few standard design elements have emerged:
- The master cylinder divides the high hydraulic pressure, which increases the gripping force.
- More clamping force is produced by brake calipers that are larger and have many pistons.
- Friction is reduced when the surface area of the brake pads increases.
- Friction is also improved by using brake pad material that is more aggressive.
- For increased stopping torque, use brake rotors with a larger diameter.
- Even when heated, the shape of thicker brake rotors remains unchanged.
- Vented brake rotors are more efficient at releasing heat.
- In order to help dissipate heat, aerodynamic elements both within and beneath the vehicle direct airflow through the brakes.
REAR BRAKE DESIGN
Though the relative importance of the front and rear brakes is determined by the vehicle’s design as a whole, the latter should never supply more than 40% of the stopping force. Because of this, they don’t become hot nearly as much as the brakes up front. Whenever you pressed down on the brake pedal, the rear brakes would lock up or the anti-lock braking system (ABS) would activate constantly if they weren’t made to handle this reduced weight.
To ensure the vehicle is stable and has the appropriate amount of braking power, you need:
- Less clamping force is produced by low hydraulic pressure that is divided by the master cylinder.
- Less clamping force is also provided by smaller brake calipers.
- Less aggressive brake pad composition and a smaller brake pad surface reduce friction.
- Brake rotors with a smaller diameter reduce stopping torque.
- Lighter and less subjected to heat, thinner brake rotors are preferable.
- The amount of heat that solid brake rotors are required to dissipate is less.
- As previously said, drum brakes are standard on a lot of affordable vehicles.
How Do Front Brakes Function?
Under strong braking, the front brakes can bear as much as 75% of the vehicle’s braking force and produce significantly more heat—up to 500°F.
The science that underpins it all is this:
As the vehicle continues to go forward when you use the brakes:
The vehicle’s center of gravity moves forward, which increases the load and speed on the front wheels. As a result, the front wheels acquire better grip and can withstand greater amounts of braking force.
In such a situation, how are front brakes usually set up to handle it?
- A powerful clamping force is applied by means of the brake master cylinder’s increased pressure.
- Front disc brakes often have large, multi-piston calipers that provide considerable clamping force.
These improvements include:
- Brake pads with larger surface areas and a more aggressive friction compound to enhance braking performance
- Brake rotors with larger diameters offer greater stopping torque
- A thicker rotor to better maintain its shape when heated up – Ventilated rotors to help with cooling
How Do Rear Brakes Function?
Compared to the front brakes, the rear brakes don’t produce nearly as much heat because they normally only apply about 40% of the braking force.
If the rear brake didn’t offer stability, it would lock up with every pedal stroke. The lack of stabilizing braking power caused by malfunctioning rear brakes might cause the vehicle’s back end to bounce while applying heavy braking pressure.
What is the typical configuration of the rear brakes?
- Reduced braking power is caused by the master cylinder delivering decreased hydraulic pressure to these brakes.
- Some physical characteristics of rear disc brakes that are designed to accommodate less force during braking include:
- smaller brake calipers and rotors attached to the rear wheel.
- Rear brake pads have a smaller surface area, rear pads made of a less aggressive friction substance, and a solid brake rotor that is thinner because it doesn’t have to dissipate as much heat.
- many compact automobiles and light trucks have a drum braking system mounted on the back axle. Although they are less powerful than disc brakes, they are more dependable and less expensive to produce.
- the parking brake (or emergency brake) is a part of the rear brake as well.
Most vehicles and light trucks can be accurately described by this design.
A different design may be necessary for larger cars to accommodate their backload capacity.
What’s A Disc Brake?
The three main components of a disc brake are the caliper, the brake pads, and the rotor.
Two primary varieties of calipers are the fixed caliper and the floating caliper.
Over the rotor, in a C-clamp configuration, is the caliper that retains the brake pads.
The caliper clamps down on the rotor with brake pads to stop it from spinning (together with the tire).
Front and, on occasion, rear axles are equipped with disc brakes. The front brakes are ideal for the harder braking effort because of their higher braking capability compared to drum brakes.
What’s A Drum Brake?
A wheel cylinder, brake shoes, and a brake drum make up the primary braking components of a drum brake, which is a bit more intricately designed than disc brakes.
At each end of the wheel cylinder is a brake shoe. To bring the tires to a halt, it presses each brake shoe on the inner surfaces of a brake drum that is in motion.
Even though it’s an older design, the drum braking system is incredibly dependable.
Disc brakes are better at managing heat dissipation, hence this component is typically found on the back axle.
Tell me how these two kinds of brakes vary.
Comparison of Disc and Drum Brakes
What follows is an explanation of how disc brakes vary from drum brakes:
- The braking capacity of disc brakes is higher than that of drum brakes because they apply braking power more quickly, resulting in shorter stopping distances.
- The disc brake components cool down more quickly since they are exposed to air, which helps with heat management. The parts of a drum brake are enclosed, thus they require more time to cool down.
- Your brake discs will stay reasonably dry in wet circumstances due to the open design of disc brakes, which improves their performance. After water seeps into a drum brake, the friction material remains exposed to moisture for a longer period of time, making the drying process more tedious.
- Disc brakes often weigh less than drum brakes and are engineered to exert the same braking force. A vehicle’s braking performance is directly proportional to its entire weight.
- The drum brake system is closed, thus dust from the brakes will build up inside and need to be cleaned periodically. Disc brakes have a “self-cleaning” quality to them because, when they brake, the brake pads “wipe” the rotor.
Here are some frequently asked questions (FAQs) about brakes, their functions, and maintenance, now that you know the many types of brakes.
Frequently Asked Questions about the Brake System
For any inquiries you might have concerning the braking system, we have provided the answers below.
1. The Braking System: How Does It Operate?
Have you ever wanted to know how the brakes function?
Hydraulic pressure is the foundation of the conventional vehicle braking system.
Pressing down on the brake pedal applies mechanical force, which initiates the braking process.
After that, the hydraulic pressure is transferred to your brake fluid by means of the brake master cylinder.
The brake line subsequently transports the brake fluid to the wheel’s braking mechanism.
To slow down, the hydraulic pressure is converted back into mechanical force by the brake system at each wheel, which creates friction.
One of these two methods is used to do this:
Brake shoes are pushed onto brake drums by drum brake wheel cylinders.
Compressing rotors with brake pads is done by disc brake calipers.
2.How Are Fixed and Floating Brake Calipers Distinct?
You can find floating calipers with one piston or two side-mounted pistons.
The floating caliper piston forces the inner brake pad to make contact with the rotor when the brakes are applied. At the same time, the outer brake pad comes into contact with the rotor as the caliper body slides closer to it.
The caliper bracket holds the stationary caliper in place. A pair of piston arrays flank it, distinguishing it from the floating caliper. The caliper pistons are the sole components that move when the brakes are applied, forcing the disc brake pads against the rotor.
Although they are more costly, fixed calipers are typically considered the superior choice due to their performance.
3: How Is the Parking Brake Operated?
Attached to the rear brake axle, the parking brake (also known as an emergency brake) operates independently of the hydraulic braking system.
When using a vehicle with a rear drum brake system, the parking brake can be engaged using a lever and cables. Drum brake shoes wedge themselves into the brake drum when the brake lever is turned on, halting the back tire from moving.
There are usually two ways that rear disc brakes with parking brakes are installed:
A corkscrew device that forces a piston in the back caliper onto the brake pad may be found within. When the parking brake is pressed, the car comes to a complete stop.
The parking brake can alternatively be activated by a separate drum brake system that is integrated into the rotor hub, an alternative to rear disc brakes.
4. How Often Should I Get My Brakes Serviced?
Between 15,000 and 20,000 miles is the recommended interval for brake inspections.
Listen carefully for any squealing or grinding sounds coming from the brakes; these could indicate worn brake pads. Also, pay close attention if the brake warning light comes on. Quickly have a mechanic inspect your brakes if any of these symptoms appear.