First of all, the compound brake discs have been developed to meet the high demands of sports cars. Their effectiveness has already been well proven in Formula One.The principle of the bi-material is to dissociate the wheel hub mounting part (the hat)from the friction part in order to greatly reduce weight whilst maintaining a very stable assembly capable of huge stopping requirements.
The friction part is as usual made of cast iron reinforced with a high carbon content which improves wear resistance. The mounting part (the hat) is made of aluminum for BMW or steel for Mercedes (in order to fit with the OE practice) and is riveted to the disc. Using aluminum or steel makes the discs lighter and also limits deformations, which cause vibrations and passenger discomfort. The assembly is manufactured with stainless steel rivets which ensure a very good transmission of the braking torque and also reduces the possibility of the disc to distort.
The left compound brake disc is for BMW models with an aluminium hat, the right compound brake disc is for Mercedes-Benz models with a steel hat
Advantages compared to the standard brake discs
- Lightweight component design results in lower fuel consumption and reduced CO² emission
- Reduced un-sprung mass improves driving comfort and performance
- Improved disc wear resistance
- The disc and the hat are joined using a special method which further reduces undesired heat transfer. This then reduces warping and hot tears, as well as vibration and noise.
Identification of compound discs
Compound brake discs are very fragile products when not mounted on the vehicle. Special requirements and safety precautions are involved in the handling and installation of these components. The label “Handle with care”is glued on all compound discs packaging to facilitate the identification of these products even before the box is opened.
Find out more at boschaftermarket.co.uk