When you build a car with the performance capability the new 2006 BMW M5 possesses, a damn good set of brakes is needed to keep things under control. Not surprisingly, BMW engineers didn’t scrimp here. The BMW M5 is fitted with 14.7-inch cross-drilled front rotors that are 1.42 inches thick while the rears are 14.6-inch cross-drilled discs with a thickness of .94 inches. The big news here is the use of compound brakes. The BMW M5 uses specially constructed aluminum and cast-iron rotors to reduce weight but the technology also eliminates deformation of the rotors under even the extremes of heavy track use.