Beautiful motorcycles. Always liked the appearance of the stamped steel frames BMW and Zundapp used in the 1930s. I'm having a mental block at the moment .... but was it Zundapp or DKW that used the chain and sprocket transmission vs having gears that meshed? From a cost standpoint, it makes sense. Instead of precision gears meshing, the tranny had chains and sprockets with different ratios inside the box. Just can't remember if it was Zundapp or DKW. I know it wasn't BMW.