Walther became interested in the development of brake drum design and construction. In the mid-1920s, Walther engineered and obtained patents for an improved truck brake drum. The wheel had limited space for a brake drum. In bad cases this ridge can make the brake drum captive. However the environment inside the brake drum can be very tough on electric parts. Other methods include mounting the brake drum on a snare drum stand. Spicer has also worked with London-based percussion ensemble Brake Drum Assembly. The handbrake is operated mechanically against a brake drum mounted directly on the transmission. The front brake drum was redesigned to allow a larger braking surface. In drum brakes, pistons push two shoes against the brake drum accomplishing the same effect. Either way, the percussionist strikes the brake drum with hammers or sticks of various weight.