This is listed on the Oakland Museum website, www.museumca.org:
Sunday, July 15
Bike Tours of Oakland
Explore Oakland and its environs with the museum's bike-tripping docents. This month's trip is to the thriving Port of Oakland. The leisurely paced two-hour tours are about five miles long, with no hills. Meet at 10th Street entrance at 10 a.m.
Reservations are required: 510/238-3514 or firstname.lastname@example.org. Free.