Central Harlem and Tweed, 1950s Gang Fashion

Gang styles could be quite surprising, given the class origins of gang members. For example, for a period in the 1950s, African-American gangs in Central Harlem wore gray flannel suits or took to the streets in the "Ivy League look," with Harris tweed sports jackets, narrow dress slacks, dress shirts, and striped ties.
...

While zoot suits shouted defiance of the dominant culture, flannel suits and tweed sports jackets subverted it. These clothes were more subtle in message, serving to confound the expectations of police, parents, and other onlookers. African-American gang members inverted the meaning of gray flannel suits - the foremost symbol of the dominant white culture - simply by having them adorn their black bodies. Instead of merging into what white critics saw as faceless corporate culture, gang members used the suits to make themselves visible, both to their working-class parents and to the dominant culture they defied.

Source:

Vampires, Dragons, and Egyptian Kings: Youth Gangs in Postwar New York, Eric C. Schneider, 2001