Brakes

Quick Summary

Carbon ceramic brake technology comes with its own vocabulary. Acronyms like CCB, CCM, PCCB, and C/SiC appear throughout product specifications, forum discussions, and technical literature, and understanding them is essential for making informed purchasing and maintenance decisions. This AME Motorsport glossary defines more than fifty terms used in the carbon ceramic brake world, organised into logical categories with practical context for each definition. Technology for Everyone starts with speaking the same language, and this reference ensures every owner can navigate technical discussions with confidence.

For a complete introduction to carbon ceramic technology before diving into terminology: Carbon Ceramic Brakes: The Complete Guide

Material and Manufacturing Terms

C/SiC (Carbon Fibre Reinforced Silicon Carbide): The base material used in carbon ceramic brake rotors. Carbon fibres provide structural reinforcement within a silicon carbide ceramic matrix. This composite delivers the combination of low weight, extreme heat resistance, and exceptional hardness that defines carbon ceramic braking performance.

Carbon Fibre: Thin strands of carbon atoms bonded together in a crystalline structure, used as the reinforcing element in the C/SiC composite. Carbon fibres provide tensile strength and fracture toughness to the otherwise brittle ceramic matrix.

Silicon Carbide (SiC): A ceramic compound of silicon and carbon that forms the matrix material surrounding the carbon fibres in a carbon ceramic rotor. Silicon carbide is extremely hard (approximately 9.2 on the Mohs scale), thermally stable, and chemically inert.

SiC Coating (Silicon Carbide Coating): An additional layer of silicon carbide applied to the braking surface of CCB-type rotors. This coating provides a smoother, more uniform friction surface, improves initial bite, reduces noise, and extends rotor life compared to uncoated surfaces.

For a detailed comparison of coated versus uncoated rotors: CCB vs CCM: SiC-Coated vs Uncoated

Pyrolysis: A manufacturing step in carbon ceramic rotor production where organic binding materials are decomposed through heating in an oxygen-free environment. This process converts the resin-impregnated carbon fibre preform into a porous carbon structure ready for silicon infiltration.

Liquid Silicon Infiltration (LSI): The manufacturing process in which molten silicon is drawn into the porous carbon preform through capillary action. The silicon reacts with the carbon matrix to form silicon carbide in situ, creating the final C/SiC composite material. This process occurs at temperatures exceeding 1,400 degrees Celsius.

Chemical Vapour Infiltration (CVI): An alternative manufacturing process to LSI, in which silicon carbide is deposited within the carbon preform from a gas-phase chemical reaction. CVI produces a denser, more uniform matrix but at higher cost and longer processing time. Used primarily in aerospace and high-end motorsport applications.

Long Fibre Carbon Ceramic: Carbon ceramic material reinforced with continuous or long-segment carbon fibres, typically exceeding 50 mm in length. Long fibres provide superior fracture toughness and structural integrity compared to short fibre formulations.

Short Fibre Carbon Ceramic: Carbon ceramic material reinforced with chopped carbon fibres, typically under 10 mm in length. Short fibre material is easier and less expensive to manufacture but generally offers lower fracture toughness. Often used in lower-cost carbon ceramic products.

For a comparison of fibre types: Long Fibre vs Short Fibre Carbon Ceramic

For a complete manufacturing overview: How Carbon Ceramic Brakes Are Made

Preform: The shaped precursor structure of carbon fibres and resin binders that is formed into the rotor shape before the pyrolysis and silicon infiltration steps. The preform determines the rotor's final geometry and fibre architecture.

Mohs Hardness Scale: A qualitative scale from 1 to 10 that ranks the scratch resistance of minerals and materials. Carbon ceramic (C/SiC) rates approximately 9.2, compared to approximately 5.5 for cast iron. This extreme hardness is why carbon ceramic rotors resist wear so effectively and why specialised pad compounds are required.

Thermal Conductivity: The rate at which a material transfers heat. Carbon ceramic material has lower thermal conductivity than cast iron, meaning heat dissipates differently through the rotor body. This property contributes to lower caliper and fluid temperatures but requires different cooling strategies than iron rotors.

Product Classification Terms

CCB (Carbon Ceramic Brake): A classification used by AME Motorsport and others to describe carbon ceramic rotors with an applied SiC coating on the braking surface. CCB rotors offer improved initial bite, lower noise, reduced pad dust, and a longer service life compared to uncoated CCM rotors. The SiC coating provides a smoother, more controlled friction surface.

CCM (Carbon Ceramic Matrix): A classification describing uncoated carbon ceramic rotors where the raw C/SiC composite surface serves as the braking surface without an additional SiC coating layer. CCM rotors expose the bare matrix structure, which has a more textured surface and may take longer to establish a pad transfer layer during bedding.

PCCB (Porsche Ceramic Composite Brake): The proprietary trade name for carbon ceramic brakes fitted to Porsche vehicles. PCCB rotors are identified by their distinctive yellow brake calipers. The term is specific to Porsche but the underlying technology is comparable to carbon ceramic systems used across other manufacturers. AME Motorsport offers PCCB-compatible replacement rotors for models including the Porsche 992 GT3/Turbo S and Porsche 718/981 Boxster/Cayman.

PSCB (Porsche Surface Coated Brake): A Porsche-specific term for iron rotors with a tungsten carbide surface coating. Important to distinguish from PCCB, as PSCB is not a carbon ceramic product despite the similar-sounding name.

CCM-R (Carbon Ceramic Matrix - Racing): A designation used by some manufacturers for carbon ceramic rotors specifically engineered for motorsport applications, with material formulations optimised for the extreme thermal demands of competitive racing.

For SiC coating technology explained: Silicon Carbide (SiC) Coating Technology

Braking System Component Terms

Rotor (Disc): The rotating component of the brake system that is mounted to the wheel hub and spins with the wheel. The brake pads clamp against the rotor surfaces to generate friction and convert kinetic energy into heat. In carbon ceramic systems, the rotor is the C/SiC composite component.

Rotor Hat (Bell, Top Hat): The central mounting section of the rotor that bolts to the wheel hub. On carbon ceramic rotors, the hat is typically made from aluminium or iron alloy rather than carbon ceramic material, as the hat serves a mounting function rather than a friction function. The hat-to-disc connection is a critical engineering interface.

Floating Rotor: A rotor design where the carbon ceramic disc is connected to the metallic hat through a set of drive pins or bobbins that allow limited radial and axial movement. This floating mount accommodates thermal expansion differences between the ceramic disc and metallic hat, preventing warping and stress cracking during heat cycling.

Drive Pins (Bobbins): The connection points between the floating carbon ceramic disc and the rotor hat. These pins transfer braking torque while allowing controlled movement to accommodate thermal expansion.

Caliper: The hydraulic clamp that houses the brake pads and pistons. When hydraulic pressure is applied through the brake pedal, pistons in the caliper push the pads against the rotor surfaces to create braking friction.

Fixed Caliper (Monobloc): A caliper design with pistons on both sides of the rotor, mounted rigidly to the steering knuckle. Fixed calipers provide more even pad pressure and stiffer pedal feel. Most high-performance carbon ceramic systems use fixed calipers with four, six, or eight pistons.

Floating Caliper (Sliding Caliper): A caliper design with pistons on only one side, mounted on slide pins that allow the caliper body to move laterally. The piston pushes the inner pad against the rotor, and the caliper body slides to pull the outer pad into contact. Less common on high-performance carbon ceramic applications but found on some OEM systems.

Brake Pad: The sacrificial friction component that presses against the rotor surface to generate braking force. Carbon ceramic rotors require specially formulated pad compounds, as standard metallic pads will damage the rotor surface.

Transfer Layer: A thin, uniform coating of pad friction material that deposits onto the rotor surface during the bedding process. The transfer layer is essential for proper braking performance. The pad's friction material grips against this transfer layer rather than directly against the bare rotor surface.

Bedding (Break-In): The controlled process of establishing the pad transfer layer on the rotor surface through a prescribed series of stops at progressively increasing intensity. Proper bedding is required after every pad change and new rotor installation.

Performance and Measurement Terms

Friction Coefficient (Mu): The ratio of the force of friction between pad and rotor to the normal force pressing them together. Higher friction coefficients produce stronger braking force for the same hydraulic pressure. Carbon ceramic pad compounds are characterised by their friction coefficient across different temperature ranges.

Fade: A reduction in braking effectiveness caused by elevated temperature. In hydraulic brake systems, fade most commonly results from brake fluid boiling (vapour lock) rather than from reduced pad friction, particularly on carbon ceramic systems where pad compounds maintain friction at high temperatures.

Vapour Lock: A condition where brake fluid boils within the caliper, creating compressible gas bubbles in the hydraulic line. This causes a soft, spongy pedal with dramatically reduced braking force. Vapour lock is the most dangerous form of brake fade because it results in near-total loss of braking.

Brake Dust: The fine particles shed by brake pads during normal operation. Carbon ceramic compatible pads typically produce less dust than conventional metallic pads on iron rotors, and the dust is generally lighter in colour and less corrosive to wheel surfaces.

Rotor Runout (Lateral Runout): The side-to-side wobble of the rotor face as it rotates, measured with a dial indicator. Excessive runout causes pedal pulsation and uneven pad wear. Acceptable runout for carbon ceramic applications is typically 0 to 0.05 mm.

Disc Thickness Variation (DTV): The variation in rotor thickness around the circumference, measured with a micrometer at multiple points. DTV causes pedal pulsation and indicates uneven wear. Maximum acceptable DTV for carbon ceramic rotors is typically 0.01 to 0.02 mm.

Dry Boiling Point: The temperature at which fresh, uncontaminated brake fluid boils. This represents the best-case thermal performance of the fluid.

Wet Boiling Point: The temperature at which brake fluid boils after absorbing a defined percentage of moisture (typically 3.7 percent). This represents real-world performance after 12 to 24 months of service and is the more relevant figure for safety planning.

Hygroscopic: The property of absorbing moisture from the atmosphere. All glycol-based brake fluids (DOT 3, 4, and 5.1) are hygroscopic, which is why brake fluid degrades over time and requires periodic replacement.

Heat Checking (Surface Crazing): A pattern of fine, shallow hairline cracks on the rotor surface caused by repeated thermal cycling. On carbon ceramic rotors, heat checking is a cosmetic condition that does not compromise structural integrity.

Glazing: A condition where the rotor surface becomes overly smooth and polished, reducing friction effectiveness. Glazing occurs from extended periods of light braking without sufficient temperature to maintain the pad transfer layer.

Unsprung Weight: The mass of vehicle components not supported by the suspension springs, including wheels, tyres, brake rotors, calipers, and wheel hubs. Carbon ceramic rotors significantly reduce unsprung weight compared to iron rotors, improving ride quality, handling responsiveness, and suspension effectiveness.

For weight savings analysis: Carbon Ceramic Weight Savings and Handling

Installation and Maintenance Terms

Torque Specification: The precise rotational force (measured in Newton-metres) to which a fastener must be tightened. Carbon ceramic brake installations require strict adherence to torque specifications for rotor mounting bolts, caliper bracket bolts, and wheel fasteners.

Anti-Squeal Compound (Brake Quiet): A high-temperature damping compound applied to the back of brake pad backing plates to reduce vibration-induced noise. Must be rated for at least 500 degrees Celsius. Applied to the backing plate only, never to the friction surface.

Caliper Slide Pins (Guide Pins): Lubricated pins on which a floating caliper body slides laterally. Seized or corroded slide pins cause uneven pad wear and reduced braking performance. Regular cleaning and re-lubrication is part of standard brake maintenance.

Brake Line (Brake Hose): The flexible rubber or braided stainless steel hose that connects the rigid brake lines on the vehicle body to the caliper on the moving suspension. Rubber hoses are slightly permeable to moisture (contributing to brake fluid degradation) and should be inspected regularly for swelling, cracking, or abrasion.

Caliper Piston Retraction: The process of pushing caliper pistons back into their bores to accommodate new, thicker brake pads during pad replacement. Requires the correct tool type for the caliper design (push-back or screw-in).

Bleeding (Brake Bleeding): The process of removing air from the hydraulic brake system. Air in the system is compressible and causes a soft, spongy pedal. Bleeding is performed by opening a nipple on each caliper and allowing fluid to flow until all air bubbles are purged.

Industry and Standard Terms

DOT (Department of Transportation): The U.S. federal agency that establishes minimum performance standards for brake fluids. DOT 3, DOT 4, and DOT 5.1 designate glycol-based fluids with progressively higher minimum boiling points. DOT 5 designates silicone-based fluid (not recommended for carbon ceramic applications).

ECE R90: A European regulation governing brake component replacement parts, requiring that aftermarket brake components meet specific performance criteria relative to the original equipment. Ensures that replacement rotors and pads perform within defined tolerances of the OEM parts they replace.

OEM (Original Equipment Manufacturer): The vehicle manufacturer that supplies the vehicle as originally built. OEM carbon ceramic brakes refer to carbon ceramic systems installed at the factory as original equipment, as opposed to aftermarket upgrades.

Aftermarket: Products manufactured by companies other than the original vehicle manufacturer, designed as replacements or upgrades for OEM components. AME Motorsport carbon ceramic rotors are aftermarket products engineered to meet or exceed OEM performance specifications.

TUV (Technischer Uberwachungsverein): A German technical inspection association that provides independent testing and certification of automotive components. TUV certification on brake components indicates compliance with rigorous safety and performance standards.

Recommended Brake Pads for Carbon Ceramic Rotors

When upgrading to carbon ceramic rotors, selecting the correct brake pad compound is essential. Standard metallic pads must never be used on carbon ceramic surfaces. AME Motorsport recommends these proven carbon ceramic compatible compounds:

• Pagid RSC Series — European racing heritage, three compounds (RSC1 street, RSC2 endurance, RSC3 sprint) covering every driving scenario
• Barbaro Racing — Italian motorsport lineage with compounds from whisper-quiet C-01 to RS-635 competition
• NetzschRacing — German precision engineering with Street, Race, and Carbon Ceramic Series
• Schaffen ZZ Racing — Asian touring car championship pedigree, validated in extreme heat and humidity

For detailed compound comparisons: Best Brake Pads for Carbon Ceramic Rotors

Frequently Asked Questions

What is the difference between CCB and CCM?

CCB (Carbon Ceramic Brake) refers to carbon ceramic rotors with an applied SiC (silicon carbide) coating on the braking surface. CCM (Carbon Ceramic Matrix) refers to uncoated carbon ceramic rotors where the raw C/SiC composite surface is exposed. The SiC coating on CCB rotors provides a smoother friction surface, improved initial bite, lower noise, reduced brake dust, and extended service life. Both types use the same underlying C/SiC composite material, but the coating gives CCB rotors measurable advantages in most driving scenarios.

What does PCCB stand for and is it the same as carbon ceramic?

PCCB stands for Porsche Ceramic Composite Brake, which is Porsche's proprietary trade name for their factory-fitted carbon ceramic brake system. PCCB uses the same fundamental C/SiC material technology as other carbon ceramic systems. It is identified by distinctive yellow brake calipers. While the brand name is Porsche-specific, the underlying engineering principles are comparable to carbon ceramic systems offered by other manufacturers and aftermarket suppliers including AME Motorsport.

Why does the Mohs hardness of carbon ceramic material matter for pad selection?

Carbon ceramic material rates approximately 9.2 on the Mohs hardness scale, making it significantly harder than cast iron at approximately 5.5. This extreme hardness means that standard metallic brake pad compounds, which contain hard metal particles designed to interact with softer iron surfaces, will gouge and damage the carbon ceramic surface instead of creating controlled friction. Pad compounds designed for carbon ceramic rotors use carefully formulated ceramic, carbon, or organic friction materials that are compatible with the harder surface and form a proper transfer layer without causing damage.

What is a transfer layer and why is it important?

A transfer layer is a thin, uniform film of pad friction material that deposits onto the rotor surface during the bedding process. Contrary to common assumption, the brake pad does not generate friction by directly rubbing against the bare rotor surface. Instead, the pad material grips against its own deposited transfer layer. A properly formed transfer layer provides consistent, predictable friction and protects the rotor surface from direct abrasion. Without a complete transfer layer, braking performance is inconsistent, noise increases, and both pad and rotor wear at accelerated rates. This is why the bedding procedure is mandatory after every pad change or new rotor installation.

What does it mean when a rotor is described as floating?

A floating rotor uses a mounting system where the carbon ceramic disc is connected to the metallic hat through drive pins or bobbins that allow limited movement in both radial and axial directions. This design accommodates the different rates of thermal expansion between the ceramic disc and the metallic hat during heat cycling. Without a floating mount, temperature changes would create internal stresses between the disc and hat, potentially causing warping, cracking, or premature failure. Virtually all modern high-performance carbon ceramic rotors use a floating design.