Sideshow biker stunts on Golden Gate and Bay bridges vex police

Back-to-back sideshows Saturday and Sunday on the Golden Gate and Bay bridges involving hordes of motorcyclists doing wheelies and spinning doughnuts created a major headache for the California Highway Patrol and drivers who were slowed down by the illegal stunts, officials said Monday.

Police got calls throughout Saturday about a large group of motorcyclists riding on and off the Bay Bridge, said Officer Vu Williams, a CHP spokesman. Around 3 p.m., officers went to the bridge after riders on dirt bikes and street bikes were seen engaging in the reckless behavior.

One motorcyclist around that time crashed into several vehicles. The rider was ejected from the bike as it became disabled and burst into flames, Williams said. The man tried to run away but was apprehended. It wasn’t immediately clear to whether he was associated with the larger crowd.

Cars drive over the Golden Gate Bridge on June 28. Police over the weekend responded to reports of motorcyclists pulling stunts on the bridge. Cars drive over the Golden Gate Bridge on June 28. Police over the weekend responded to reports of motorcyclists pulling stunts on the bridge. Photo: Justin Sullivan, Getty Images Photo: Justin Sullivan, Getty Images Image 1 of / 1 Caption Close Sideshow biker stunts on Golden Gate and Bay bridges vex police 1 / 1 Back to Gallery

Around the same time Sunday, a stream of motorcyclists went onto the Golden Gate Bridge — which sees far fewer sideshows than the Bay Bridge. Witnesses reported seeing some of the bikers popping wheelies or doing hand stands as they rode. Police are looking into whether it was the same group as the day before, said Officer Andrew Barclay, another CHP spokesman.

The group rode north across the bridge, got off, then got back on the iconic span going south, police said.

Barclay said the last sideshow event he could remember on the Golden Gate Bridge was in 2014.

“Obviously it’s extremely unsafe, especially on the Golden Gate Bridge, where you have pedestrians,” he said. “To have amateurs doing this type of exhibition is extremely dangerous.”

Stunts happening on the bridges — rather than in a vacant parking lot, for instance — pose challenges for police and often require sharp-eyed witnesses.

“People see it, they call and that’s usually it,” Barclay said, “because by the time we get there they’re usually gone.”

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov