Here's how to get your stolen bike back in S.F.

S.F. police Officers Gary Cheng (left) and Matt Friedman question a man about a bicycle he was dismantling. S.F. police Officers Gary Cheng (left) and Matt Friedman question a man about a bicycle he was dismantling. Photo: Paul Chinn, The Chronicle Buy photo Photo: Paul Chinn, The Chronicle Image 1 of / 15 Caption Close Here's how to get your stolen bike back in S.F. 1 / 15 Back to Gallery

About a year ago Meredith Obendorfer had her bike stolen.

From a locked rack on top of her car.

In the Presidio.

At 7 a.m.

"I couldn't believe it," she says. "It was my $5,000 mountain bike. These guys do it in plain view with disregard to the fact that they are taking someone else's property. I'm like, I busted my ass to buy this bike, and you're just taking it."

Surely there is a special ring of hell for the sleaze balls who rip off bikes. They prey on people who are not only trying to do the right thing by staying out of cars, but who often use bikes as their main means of transportation. Virtually anyone who regularly rides a bike in San Francisco is familiar with the sinking sensation of coming out of a building and finding a broken lock where their bike used to be.

"I've had a car stolen and a bike stolen, and I think a bike is way worse," says Kelly Snow, who lost five expensive bikes from her garage. "Ours were custom, because my boyfriend built them. Losing your bike is more personal, like losing photos of your family."

Bike theft is a growing problem in the city, but, finally, people - and the police - are taking matters into their own hands by targeting thieves and finding ways to get those bikes back.

By the way, it isn't their imagination - bike thefts are increasing.

A report prepared for the Board of Supervisors last year found that bike theft has increased 70 percent in the city in the past five years, resulting in an estimated financial loss of $4.6 million.

Combination of tactics

Oh, well. Life in the city, right? You know the conventional wisdom: Once a bike is stolen it vanishes into a network of chop shops and fencing operations, and cops don't make bike theft a priority. And even if they did, there's no way to track or trace stolen bikes.

All untrue.

Using a combination of social media, police tactics and sophisticated tracking, some victims aren't only targeting thieves, some are getting their bikes back. Granted, examples are few, but even small victories are encouraging.

Two years ago, Jenny Oh Hatfield's expensive new mountain bike was stolen. She was furious - also motivated.

"I e-mailed every cycling group I knew, posted my story on Twitter, Flickr, Facebook and Google+," she wrote in a blog post. "A part of me was resigned ... but I received so many messages of support that I wasn't ready to consider it gone forever."

Hatfield posted photos of the bike and details about it - that was key.

"And a week later, a woman who had seen the post on Facebook was at the Laney College flea market and saw someone walking with my bike," Hatfield said. "She said, 'Hey, that bike is stolen, and we're taking it right now.' And he just gave it to her."

'I got my bike back'

Hatfield became a bike recovery evangelist.

"Hey, I got my bike back in a week," she told people. "You might be able to too if you put in a little effort."

For starters, she says she realized there are no comprehensive resource to turn to, so she started one. Her Google group, Stolen Bicycles Bay Area, is full of useful information, like how to set an alert on Craigslist and eBay that will notify you if a bike matching yours appears on the site.

She also got in touch with San Francisco police Officer Matt Friedman, who has become the city's bike theft guru. One of the smart things Friedman did was set up a Twitter account,@SFPDBikeTheft, which is not only a place to log stolen bikes, but a public spot to post photos of crimes in progress.

"We had an instance where I had a photo of a guy breaking into a bike in the Mission," Friedman said. "Within 10 minutes we had it out with the picture attached, and he was arrested. A photo is the best kind of evidence you can have."

Known criminals

Friedman says he's not concerned about legal liability. Although he tweets photos of frequent offenders, they are known, convicted criminals. And he says the photos of thieves caught in the act are unlikely to result in someone being unjustly accused.

"We had a guy using a cordless power saw to chop off the lock on a bike," he said. "I don't think anybody is going to be hacking the U-lock on their own bike."

Besides, he says, "we're not accusing anybody. We're just seeing the photo and investigating. That's perfectly within our rights."

Friedman is also employing another smart tech tactic: bait bikes. They're bicycles with tiny GPS transmitters that are placed in high-risk areas and can be tracked when stolen.

"Bait bikes have been around for a while," he said. "But now we're publicizing the hell out of them."

Friedman is also handing out "bait bike" stickers that riders can put on their rides to make it look like there are lots of tracking bikes in circulation.

He's also working on chop shops, like the infamous one under the Central Freeway at Duboce. Obendorfer reported that one, sending a photo to Friedman's Twitter feed.

"It is just so obvious," she said. "There are encampments, and you see them sitting there, working on bikes."

Friedman checks the site regularly, but consistently runs into a problem: When he runs serial numbers, bikes come back as unregistered.

Serial number is key

"You need to know your serial number and put it on a registry," Friedman says. "You can go to safebikes.org and register online. It takes five minutes."

Then if your bike is stolen and you file a police report, authorities can run a quick check. The Police Department has hundreds of recovered bikes that can't be returned to their owners because they aren't registered.

And, if you do all that, you might be surprised. Snow says when her garage was burglarized the total loss was nearly $15,000. She set up an alert on Craigslist and got a hit 30 days later. She arranged for the police to meet the thief at a pawnshop and not only got the bike back, but had him arrested.

Although it was only one of the five, Snow was pleased. And so was Friedman.

As he says, "It's always nice to see the expression on someone's face when you give them back their bike."