Noun
a hollow cast iron cylinder attached to the wheel that forms part of the brakes
Source: WordNetBrake drum The brake drum is generally made of a special type of cast iron that is heat-conductive and wear-resistant. Source: Internet
Current design theory is to use shoes for the proper diameter drum, and to simply replace the brake drum when necessary, rather than re-arcing shoes. Source: Internet
Machining the friction surface of a brake drum increases the diameter, which might require oversized shoes to maintain proper contact with the drum. Source: Internet
Shimano Nexus front hub with roller brake The brake drum itself is frequently made of cast iron, though some vehicles have used aluminum drums, particularly for front-wheel applications. Source: Internet
Usually it is only necessary to machine away the ridge that forms that makes brake drum removal difficult. Source: Internet