Fault assessment of brake discs
Brake disc service life is too short
The useful life of brake discs and brake pads is only one – albeit very important – aspect in the development of a brake system. For normal usage conditions, the design life of the front wheel brake discs should be equivalent to the useful life of two sets of corresponding brake pads. Some discs may have a shorter useful life, because they have been designed to achieve specific targets on which more value is placed, for example to prevent unwanted effects such as cold judder.
In practice, the useful life of a brake disc depends on the following influencing factors:
- the driving style
- road and traffic conditions
- topographic and climatic conditions
- the level of dirt and contamination
- the brake disc’s casting material and structure
- the aggressiveness of the brake pads
- the freedom of movement of the sliding and guide elements and the brake actuating piston
Because of the many influencing factors, in practice, brake disc life turns out to be a statistical figure; the distribution function shows that some discs last 10 to 15 times longer than others. Some discs reach the end of their useful life after just 20,000 kilometres, others may provide trouble-free service for as much as 300,000 kilometers, while even lower or higher mileages are possible in individual cases. This makes it impossible for manufacturers and distributors to offer any guarantee for the useful life of their brake discs.