A group of bōsōzoku in 2013 Bōsōzoku (暴走族, lit. 'running wild and driving recklessly tribe') is a Japanese youth subculture associated with customized motorcycles. The first appearance of these types of biker gangs was in the 1950s. Popularity climbed throughout the 1980s, peaking at an estimated 42,510 members in 1982. Their numbers dropped dramatically in the 2000s, with fewer than 7,297 members