1972 Paradise Drive Cyclocross in Tiburon, CA.

 Joe Breeze (#48 and winner of this particular race) should be noted for his well-worn wool shorts and heavily-roped rear tire, which was apparently necessary to gain traction on the slippery course. Rider #47 also has given the same treatment to his rear. Singlespeed was apparently the way to go, as shown by three of the four riders in the photo, including Otis Guy (#45)