Dress shoes, boat shoes, hiking boots, and sneakers. What do they have in common? You wear them on your feet, of course. But brake shoes? Well, not so much. Brake shoes are worn on your car and are there for one purpose: to stop your four-thousand-pound metal machine when you step on the brake pedal. But what do they have in common with brake pads ? Are brake shoes and brake pads the same thing?
What brake shoes and pads have in common
Brake shoes and brake pads are not the same. They are both similar components of an automotive braking system , but they do their jobs in different applications. In fact, your car may not even have brake shoes at all. It might be entirely shoeless.
They do, however, serve the same purpose. Brake shoes and pads each help to create friction and convert the kinetic energy of your vehicle-in-motion into thermal energy to slow you down and bring you to a stop. When you press on the brakes , hydraulic fluid exerts pressure through a system of hydraulic lines and hoses to each wheel where either a pair of brake pads or a pair of brake shoes is waiting to dampen the movement of the wheel.
Because they apply pressure to moving metal components, both brake shoes and brake pads wear out over time. That’s okay, they are supposed to. Shoes and pads contain a sacrificial friction material that wears away with use so that other functional components of the drive system do not. That means, both brake shoes and brake pads need to be replaced periodically during a complete brake job . And the nature of the job they each do to protect you and your passengers is why you need to make sure that each brake job is done right.
Brake shoe and brake pad composition
Another thing that brake shoes and pads have in common is the composition of the friction material they contain. Both shoes and pads are made of a metal plate – curved in the case of shoes and flat in the case of pads – that is held in place with special hardware. To this metal plate, the friction material is bonded.
Friction material in a set of brake shoes or pads can vary. Each type of material has its pluses and minuses. The three main types of friction material are organic, semi-metallic, and ceramic.
Organic pads are often included on a passenger car from the factory. They are relatively quiet and comfortable, but they have the shortest lifespan of the three and tend to be dusty as they wear down. Organics are generally the least expensive as well.
Semi-metallic shoes and pads may come directly from the factory, especially on larger vehicles, like SUVs and trucks. They have superior gripping power, but at the cost of increased noise. Semi-metallics are also harder on other brake system components. They make for a suitable option on not only large vehicles, but on high-performance cars.
Ceramic brake pads and shoes are the quietest, most comfortable, longest lasting option, but they bear the biggest price tag to boot.
Drums Vs. Discs
The difference between brake shoes and brake pads is found in their application more than their purpose, for brake shoes are used in a drum brake system and brake pads are used in a disc brake system.
A drum brake consists of a round, hollow drum affixed to the end of an axle. Inside the drum, a pair of brake shoes is suspended, hovering just inside of the drum wall. Imagine placing your hands on the outside of a large rubber ball. What if, instead of holding the ball from the outside, your hands were pressing gently against the inside? That is how the brake shoes are placed inside the brake drum.
Attached to one end of the shoes is a piston. When you press on the brake pedal, hydraulic fluid forces the piston to extend and pushes the ends of the shoes apart from one another and firmly against the inside of the drum, thus creating friction that slows the spinning of the attached wheel.
A disc brake, on the other hand, is made up of a heavy metal disc (the brake rotor ) attached to the end of an axle. The disc spins with the attached wheel. Sandwiched around the disc is a pair of brake pads. The pads hover in place inside a clamping mechanism called a brake caliper . When you step on the brake pedal, the force is transferred to the caliper. The caliper, in turn, squeezes the brake pads against the flat outsides of the disc to create friction. This is very similar to how a bicycle hand brake works, or how a person in a wheelchair might grab hold of the wheels to slow down.
Both brake drum systems and brake disc systems have their pros and cons. Where drum brakes, for instance, tend to be less expensive to build, they are less effective at dissipating heat and less effective in wet conditions. Disc brakes perform better in wet conditions, are less likely to lock up in heavy braking, and provide less brake fade, a condition brought about when the system has a hard time managing heat. Of course, disc brakes are more expensive than drum brakes and affect the cost of new cars and brake repairs.
Drum brakes (and their shoe components) have less ability to stop a vehicle, even though they technically have more surface area to work with. But the shoe may be able to outlast pads. That is possible because of where they are typically located on a vehicle. Decades ago, many cars and trucks were made with four-wheel drum brake systems. Today, however, if a vehicle has drum brakes at all, they are found on the rear. Most of the stopping power of a brake system is found in the front end, so rear drum brake shoes can outlast their front disc brake pad counterparts.
When it comes to brake service , brake shoes are better equipped to resist corrosion because they are enclosed inside the drum. However, because drum brakes systems are more complex than disc brakes, and because they contain more moving parts, they are more difficult and time consuming to repair and replace than disc brakes, which are far more accessible for brake maintenance.