What is a Brake Disc?
The shiny metal plate your brake pads squeeze to slow you down.
Simplified animation — not to scale.
In plain English
A brake disc (or "rotor") is a flat metal disc bolted to each wheel hub. When you press the brake pedal, the brake pads clamp onto it. The friction turns your car's motion into heat, slowing the wheel down.
"Think of pinching a spinning vinyl record between two fingers to stop it — your fingers are the pads, the record is the disc."
How it works
Pressing the pedal pushes brake fluid through the system, which forces the caliper's pads against both sides of the spinning disc. That squeeze creates friction; friction slows the wheel. Discs are usually made of cast iron and get glowing hot under heavy braking — that's why they have vents to shed heat.
Signs of trouble
- ⚠Pulsing or vibration through the brake pedal
- ⚠A rhythmic squeal or grinding noise
- ⚠Steering wheel shaking under braking
- ⚠A visible deep lip or scoring on the disc edge
- ⚠Car pulling to one side when braking
£100–£250 per axle, usually replaced with pads
Always get a written quote. Prices vary by car, region, and parts brand.