Remtrommel

Remtrommel, or brake drum, is the rotating cylindrical component of a drum brake system used on many road vehicles. The drum is attached to the wheel hub and turns with the wheel. When the brakes are applied, brake shoes are pressed outward by hydraulic pistons inside wheel cylinders and contact the inner surface of the drum, creating friction that slows the vehicle. The drum also serves as a heat sink, helping to dissipate the heat generated by braking.

Drum brakes can be self-energizing, meaning the motion of the rotating drum helps push the shoes into contact, increasing braking torque. The friction surfaces are on the inside circumference of the drum, and wear on these surfaces, as well as on the shoes, affects braking performance. Design variations include different wall thicknesses and cooling features, such as vented or finned drums, to improve heat dissipation in heavier or high-load applications.

Materials commonly used for remtrommels are cast iron, chosen for wear resistance and heat capacity; aluminum drums may be used in some lighter or performance-oriented applications to save weight but are less common due to heat and durability considerations. Remtrommels are still widely used on the rear axle of many passenger cars, older vehicles, trailers, and some heavy-duty applications, often in conjunction with a parking brake mechanism integrated into the drum assembly.

Maintenance and inspection involve checking for cracks, scoring, or out-of-round wear on the drum interior, and ensuring the drum meets manufacturer specifications. Contamination by oil or grease can reduce friction and require replacement of the drum and shoes. Regular inspection of associated components, such as wheel cylinders and springs, helps maintain braking reliability.