Performance Comparison of Drum and Disc Brakes for Heavy Duty Commercial Vehicles

An alternative to the current drum brakes, with the increased requirements of todays daily service are disc brakes, in that they offer, in contrast to the drum brakes, the following technical advantages and in turn enhance the active safety of modern commercial vehicles when braking:

• Enhanced brake pedal-feedback and actuation
• Improved efficiency
• Little performance losses when high thermal loads occur (fading).

In order to be able to determine the improvement potential of disc brakes they will be compared to the commonly employed Simplex drum brakes. Both wheel brake systems (disc-/drum brakes and all variations) were tested on a computer controlled brake dynamometer and in field tests using a heavy duty commercial vehicle (class 8). The results are compared and conclusions drawn regarding “advantages/disadvantages”. These verification tests have also shown, that test results acquired with brake dynamometers coincide with field test results, when the test procedures on the brake dynamometer correspond exactly to the encountered field test conditions.