Danny Lyon, whose work served as the basis of The Bikeriders, enjoyed a long career beyond the events of the film. After spending several years traveling with and photographing the Outlaws Motorcycle Club, Lyon’s original work was published in a 1968 photo book titled The Bikeriders. As an artist, Lyon is known for immersing himself in his subject, even becoming a full Outlaw member from 1966-1967. His photography and recorded interviews during this time helped inform the acting of The Bikeriders cast and the production teams greater understanding of The Bikeriders cultural context.
https://screenrant.com/the-bikeriders-danny-lyon-what-happened-after/