San Francisco Mayor Gavin Newsom’s famous hair was tucked away under a baseball cap and City Attorney Dennis Herrera sported shorts as city officials joined bike advocates Thursday morning to celebrate Bike to Work Day. At a news conference outside City Hall, the mayor said commuting by bicycle breeds a sense of community that is lost on those in cars. “The one thing that biking does more than anything else is it connects you to other people,” Newsom said. “You don’t get connected when you’re in two SUVs.” Newsom was dressed casually, trading in his sleek business suit and even sleeker hairdo for a plain blue long-sleeve shirt and a Giants baseball cap.