How to Guides

Disc Brake Rotor

Zaki Moulvi posted this on Jun 16, 2014

The disc brake rotor is a critical element in the disc brake system.  This is the round metal plate that makes contact with the disc brake pads to stop your car.

Disc Brake Rotor History

It was early in the history of cars that disc style brakes were developed and used, but it took over 50 years for the rest of the industry to catch on.  Developed in England during the 1890’s, the disc brake was patented by Frederick William Lanchester and used on his Lanchester automobiles.  Copper was the first metal used, which did not hold up well on dusty roads making the system seem non-viable at the time.

Chrysler was the first U.S. car manufacturer to utilize the system in 1949 on their Chrysler Crown Imperial.  Following Chrysler was the 1950 Crosley Hot Shot who originally adopted a system that was designed for aircraft.  It was poorly researched and had tremendous problems with reliability causing most drivers to convert their Hot Shot back to the drum brake.

Chrysler had more luck with their four wheel disc brake system although the design is very different then what we know today.  They were very efficient at stopping an automobile but the cost to produce them made them difficult to maintain as a standard feature, and Chrysler began to only offer them at an additional cost started in 1954.

Caliper enhanced disc brakes were developed in the UK and began to be used in 1953 on the Jaguar C-Type racing car.  Other car manufacturers followed suit, and by the mid 1960’s they were found on many American made cars like the Ford Thunderbird, Lincoln Continental and Chevy Corvette. Originally, disc brake systems were used primarily on race cars, but today they have become the more choice for almost all passenger vehicles.

Drum Brakes Versus Disc Brakes

What car manufacturers quickly realized was that with the right materials, disc brake systems had a better stopping performance than the drum brakes.  The main reason for this is the fast way in which they are able to cool down and recover from getting wet.  In addition, driver’s have a better feel for the brake and can avoid lock-ups as the force of braking is in direct proportion to the amount of pressure they apply to the brake pedal.

The Disc Brake Rotor

The rotor is the part of the disc brake system where the pressure of the brake pads is applied.  Typically they are solid plates of grey iron but some higher performance vehicles will use slotted brake rotors or drilled to help dissipate the heat generated when braking.

  • Drilled brake rotors were first seen in the 1960’s on race cars.  During production holes are drilled through the rotor.  While this may cut down on the surface area needed for friction, the holes allow for heat and water to leave the surface of the rotor quicker, giving a driver better over-all performance. The downside is a weakened metal which will cause the rotors to crack over time.  This is not a concern for race cars since they will change rotors in between races, but for the everyday driver this would present a problem.
  • Slotted brake rotors have the same positive effects as drilled ones, except they are more durable.  Instead of punching holes through the metal, grooves are etched into it.  Those grooves capture heat and water and force them to be dispelled away from the surface of the rotor.  This is a better choice for performance car drivers who want the benefit of heat transference without the headache of having to change out the rotors often.

Disc Brake Rotor Maintenance

The rotors can be damaged in many ways, causing poor performance in the brake system.  Scarring, cracking, warping and rusting are all common issues seen with brake rotors.  In some instances the brake rotor can be resurfaced, using machining to polish out any imperfections in the surface and restore the shape.  This is not possible all the time, as frequent turning of the brake rotors will cause them to be too thin and crack under the pressure.

Disc Brake Rotor Maintenance

The rotors can be damaged in many ways, causing poor performance in the brake system.  Scarring, cracking, warping and rusting are all common issues seen with brake rotors.  In some instances the brake rotor can be resurfaced, using machining to polish out any imperfections in the surface and restore the shape.  This is not possible all the time, as frequent turning of the brake rotors will cause them to be too thin and crack under the pressure.

Categories: Autowiki Car Systems