I am researching the history of cycling too. Although, my focus is on Cape Town and my work will be part of a book called cycling cities Africa. Have you seen the book "Cycling Cities: The Johannesburg Experience" ?? I have a digital copy If you would like to read it.
I am at the point where I am putting together a photographic essay to go with my text, If anyone reads this and has old pictures or information (from 1900-2024) about cycling, cyclists, and anything related to cycling please feel free to share.
