Which brake system of a motor vehicle functions without any appreciable wear?

The combination of the engine brake and the retarder is correct because both systems effectively slow down the vehicle without significantly causing wear on the brake pads or other components. The engine brake utilizes the engine's resistance to decelerate the vehicle, while the retarder, which is often integrated in heavy vehicles, provides additional braking power through hydraulic or electromagnetic means.

According to German traffic regulations, using these systems is essential for maintaining a vehicle's braking efficiency and prolonging the lifespan of conventional braking systems. These methods are particularly important in situations where frequent braking is necessary, such as in mountainous terrains or during long descents, where excessive heating and wear of the traditional braking system can lead to brake failure. Understanding and utilizing these systems can enhance road safety and vehicle performance.