From SFBC :
America’s Cup 34 races are coming to San Francisco Bay this summer and next, together with hundreds of thousands of visitors and spectators. Bicycle transportation will be a key element in the success of the AC34 events, and the Bay Trail Bikeway will be the backbone of bicycle access for all. Come ride the Bay Trail and learn what is planned to lift this key Connecting the City  route to a top-notch biking experience for everyone, and how you can help the SF Bicycle Coalition get it done.
This is the “South” ride, from the Ferry Building to Heron’s Head Park; see April 14 and May 26 for the “North” ride. SF Bicycle Coalition recreational rides are free for SF Bicycle Coalition members (a $5 donation from non-members is appreciated); rain cancels rides.