The brake rotor or disc looks similar to a wide brimmed hat, with the portion that looks like the brim serving as the friction surface. The center “hat” component is typically sandwiched between the wheel and the hub or is securely mounted to the axle.

The brake pads are the consumable portion of the Disc Brake system. The pads are comprised of a backing plate that is specifically designed to fit into a given brake caliper configuration. The friction material, which determines the characteristics of the brake system is affixed to the backing plate. The friction material rubs against the brim of the brake disc/rotor, creating friction.

The brake drum looks like a bowl (from the back or inside) with vertical sides. It is typically drilled to fit over the wheel studs and sandwich between the wheel and the hub. The moving components of the drum system are mounted to a backing plate, with the components fitting inside the drum.

The brake shoes are the consumable portion of the Drum Brake system. The shoes are comprised of a flat backing plate that is bent to a specific radius to fit into a given brake drum configuration. The friction material, which determines the characteristics of the brake system, is affixed to the large (outside) radius of the backing plate. The friction material rubs against the inside of drum around the circumference, creating friction.

Modulation is the process of a driver accurately controlling the amount of brake power required without locking the wheel. Brake modulation is having the ability to consistently increase and decrease the amount of bite from your brake pads at will. The driver has complete control of his/her brake pedal at all times. By controlling the amount of force being applied by the calipers, the driver can use the brakes to their advantage in the braking zone and into the first part of the corner. It’s as if the brake pedal is giving feedback to the driver which can be beneficial to a drivers lap times, and therefore help you keep your race car under control and on the track.

As many top level and pro drivers will tell you, being able to modulate and trail brake into the first part of the corner is essential to producing the fastest possible lap times. Yes, we were all taught to brake, down shift, and then turn into the corner. That is the best way to start off, and that’s probably the safest way to start your racing career. But the fact is that there are truly only a handful of corners where you do all the braking before turning in. To run with the best you need to learn how to keep modulating your brake pedal as your entering the first part of a corner. Modulation is what Carbotech built its solid reputation on. Modulation is a cornerstone for Carbotech Performance Brakes.

Brake fade is the sensation that over the course of time, the effective stopping power of the brake system is diminishing, leading to the need for longer stopping distances. See Troubleshooting.

A soft brake pedal indicates that the brake pedal when depressed by the operator sinks lower (generally closer to the floor) than normal. If the pedal sinks slowly while being pressed, it suggests a leak in the hydraulics of the brake system. See Troubleshooting.

A spongy brake pedal feels much like the term describes. The pedal doesn’t seem to have a finite maximum pressure point. This is typically the result (symptom) of air or moisture in the hydraulic system. See Troubleshooting.

A hard or firm brake pedal is the desired state when the brake system is in good working order. When pressure is applied to the pedal, it sinks to a predicable position well above the floor and stays there in spite of continuing pressure.

Brake bedding is the process of heat cycling the friction material in a new brake system to boil out the resin gases, serving as final “cure” after manufacturing. This process also transfers material to the rotors or drums (if they are being used for the first time since manufacturing or refinishing) and creates an improved match of the transfer layer of the friction material surface to the rotor/drum friction surface. See Bedding Procedure.

Brake glaze is the condition where the friction surface of the brake pads or shoes and/or rotors or drums becomes coated with overheated friction material. The efficiency of the braking system is deteriorated when the surfaces become glazed. On the friction material, glazing appears visibly as a shiny surface. On the rotors or drums, glazing will appear as a coating on the metal friction surface, and will frequently have some cracks.

Heat checks are short, thin, sometimes numerous, radial interruptions of the rotor braking surfaces. They are the result of disc brake operation. They are caused by the heating and cooling that occurs as the brakes are applied time after time. Heat checks will frequently wear away and reform, or they may become braking surface cracks, depending on such factors as the lining and rotor wear rate, brake balance, and how hard the brakes are used. There are two kinds of heat checking: light and heavy.

Light Heat Checking- Cracks on the surface of the rotor that result from light heat checking are small and fine and do not require rotor replacement.

Heavy Heat Checking – Heavy heat checking is surface cracks that have width and depth. If you find heavy heat checking, replace the rotor.

Brake pad bite – harshness is how rough or unpleasing the brake application and pedal feel is; Cold Bite: How good the friction level is when the brake pad is cold.  Hot Bite: How good the friction level is when the brake pad is hot.

Brake torque is the force applied at the brake wheel to stop the motion of the moving equipment. Assuming the operating conditions for the equipment are constant, a brake having a retarding torque equal to the full load torque of the motor to which it is applied is usually satisfactory.


The four key elements to consider in a braking system designed to handle high temperatures properly are: surface area, thermal mass, material selection and cooling air. See Friction Compounds for details.

The coefficient of friction (also known as the frictional coefficient) is a dimensionless physics value which describes the ratio of the force of friction between two bodies and the force pressing them together. The coefficient of friction depends on the materials used — for example, ice on metal has a low coefficient of friction (they slide past each other easily), while rubber on pavement has a high coefficient of friction (they do not slide past each other easily). See Friction Compounds for details.

A brake line is a flexible hose used to transfer brake fluid from the stationary hydraulic system mounted to the vehicle chassis to the caliper or slave cylinder mounted on the suspended (moving) chassis components where the wheels reside. Original Equipment brake lines are typically rubber. In high temperature applications (race track or autocross) the rubber can become spongy and contribute to a soft or spongy brake pedal. Stainless Steel braided brake lines are frequently used in these applications to eliminate that sensation.

Brake fluid is a hydraulic fluid designed specifically for vehicular braking applications. Brake fluid is hygroscopic, meaning it absorbs water. When new from the bottle, it can be considered “dry” with a higher boiling point. Over time, brake fluid absorbs water lowering its boiling point to the “wet” level. Different brake fluids are formulated to boil at different temperatures. You should base your choice of brake fluid on the wet boiling point. See Brake Fluid for more information.

The boiling point, expressed in degrees (F or C) for brake fluid that has been in use for a period of time, and thus exposed to air or moisture. For reference, the boiling point of water is 212 degrees Farenheit or 100 degrees

The boiling point, expressed in degrees (F or C) for new brake fluid that has not been exposed to air or moisture.