I'm heading in for Alcatraz later this week, and my wife, who is just spectating, would like to rent a bike to check out the bike course with me on Friday or Saturday. Googling gets mostly the tour bikes for people who want to toodle over the bridge. Any of you locals have a recommendation on where she could rent a serviceable road bike? We're staying w friends near the Presidio, so a locale close to there would be ideal.