What is a Brake pad made of?
What is a Brake pad made of?
A friction compound of fibres, fillers and resin, moulded and bonded onto a steel backing plate.
The material history of brake pads is a history of banned ingredients. Asbestos was the original fibre and was phased out of most markets from the 1980s. Copper replaced much of it, then turned out to be a significant pollutant in road runoff, and US legislation now limits pads to under 0.5% copper by weight from 2025, with the familiar "N" and "B" edge codes marking compliance. Pads never grip through the friction material alone: braking transfers a thin layer of pad material onto the disc, and bedding-in new pads is the process of laying that layer down evenly. Skipping it is how new brakes end up with a pulsing pedal that gets blamed on warped discs.
Component by component
| Part | Material | Why that material |
|---|---|---|
| backing plate | stamped steel, often with a stainless or zinc coating | It spreads the caliper piston load across the whole pad and is the part that has to survive corrosion in a wheel arch. |
| binder | phenolic resin, cured under heat and pressure | Phenolic holds its strength to around 300 °C; when it is driven past that it decomposes and releases gas, which is brake fade. |
| reinforcing fibres | aramid, steel wool, glass, mineral or copper fibre depending on type | The fibre network stops the pad crumbling; steel gives bite and noise, aramid gives quiet and dust that is easier on wheels. |
| friction modifiers | graphite, rubber crumb, metal sulfides, ceramic particles | They tune how the coefficient of friction changes with temperature — a pad that grips harder as it heats is much harder to drive smoothly. |
| shim and slots | rubber-coated steel shim, chamfers and a slot across the face | They break up the resonance that makes brakes squeal, which is a vibration problem rather than a friction one. |
Other cars and driving objects
- Car tire Several different rubber compounds reinforced with steel and textile cord — closer to a composite than to rubber.
- Car battery Lead and lead dioxide plates in dilute sulfuric acid, in a polypropylene case — mostly lead, by weight.
- Airbag A coated nylon bag inflated by a small solid-propellant gas generator in about thirty milliseconds.
- Windshield (windscreen) Two sheets of ordinary glass laminated to a tough plastic interlayer, which is what stops it falling out.
- Spark plug A ceramic insulator carrying a centre electrode of nickel, platinum or iridium inside a steel shell.
- Seatbelt Woven polyester webbing designed to stretch a controlled amount, plus a locking retractor and a pyrotechnic pretensioner.
Common questions
- What is a Brake pad made of?
- A friction compound of fibres, fillers and resin, moulded and bonded onto a steel backing plate.
- What is the backing plate of a Brake pad made of?
- Stamped steel, often with a stainless or zinc coating. It spreads the caliper piston load across the whole pad and is the part that has to survive corrosion in a wheel arch.
- What is the binder of a Brake pad made of?
- Phenolic resin, cured under heat and pressure. Phenolic holds its strength to around 300 °C; when it is driven past that it decomposes and releases gas, which is brake fade.
Related pages
- Car tire Several different rubber compounds reinforced with steel and textile cord — closer to a composite than to rubber.
- Car battery Lead and lead dioxide plates in dilute sulfuric acid, in a polypropylene case — mostly lead, by weight.
- Airbag A coated nylon bag inflated by a small solid-propellant gas generator in about thirty milliseconds.
- Windshield (windscreen) Two sheets of ordinary glass laminated to a tough plastic interlayer, which is what stops it falling out.
- Spark plug A ceramic insulator carrying a centre electrode of nickel, platinum or iridium inside a steel shell.
- Seatbelt Woven polyester webbing designed to stretch a controlled amount, plus a locking retractor and a pyrotechnic pretensioner.
- Pencil Stationery and paper
- Tennis ball Sport and games
- Banknote Around the house
- Golf ball Sport and games
- Paper Stationery and paper
- Glass Building materials
Sources
- Typical range compiled from manufacturer specifications — At One Place