Claim: Adler offered a three-speed gearbox bicycle in the 1930s, attempts to develop gearbox bicycles was for downhill racing which is a genre of mountain biking practiced on jumps, drops, rock gardens and other obstacles.
Evidence: Adler offered a three-speed gearbox bicycle in the 1930s. Several attempts to develop gearbox bicycles during the 2000s for downhill racing, such as the Honda RN-01 G-cross, incorporated complete derailleur gear drive trains in an enclosure. Downhill mountain biking (DH) is a genre of mountain biking practiced on steep, rough terrain that often features jumps, drops, rock gardens and other obstacles.