San Francisco Randonneurs is a cycling club that organizes randonneuring events in the greater San Francisco Bay Area. Randonneuring is long-distance, unsupported endurance cycling. Events are timed but non-competitive, and emphasize self-sufficiency and camaraderie. Members of the San Francisco Randonneurs are encouraged to join this RidewithGPS club and you can become an SFR member here.
For more information, see the San Francisco Randonneurs website or that of RUSA, the governing body of randonneuring in the United States.