Minneapolis routinely ranks among the most bike-friendly cities in the country, but it turns out that bike thieves like it here, too.

Bike theft is at a five-year high, and Police Department data obtained by the Star Tribune shows almost 4,300 bikes reported stolen since 2017.

The rash of thefts frustrates cyclists and police, who don’t always have time to track down stolen bikes amid other more serious calls. But for thieves, selling stolen bikes — some valued at more than $4,000 — can be a quick way to make hundreds of dollars.

“It’s the perfect crime without much consequence, and there is a high return,” said J Allard, founder of Project 529, which bills itself as the world’s largest online bicycle registry. Unregulated online marketplaces such as eBay, Offer Up and Craigslist “make it easy to host a garage sale … and sell stolen property with little risk of getting caught.”

Allard said more than 2 million bikes are stolen every year in North America — the equivalent of one every 30 seconds — at a cost to communities of $1 billion. Plus, he said, the problem is vastly underreported, estimating that only 1 in 5 victims report bike theft to police.

Sgt. Darcy Horn of the Minneapolis Police Department said victims should absolutely report stolen bikes. Every case is reviewed by the department’s Property Crimes Unit and logged into a database that allows police to cross-reference bikes that turn up at pawnshops. But with the high volume of bike thefts, not all are investigated, she said. “Each case is reviewed and it depends on the evidence that is available,” she said. “There is a limitation on cases due to staffing.”

Oftentimes, the theft victim has to take on the role of private investigator and call in help from online forums like the Twin Cities Stolen Bikes group on Facebook.

That’s what Robin Auer did when someone snatched his bike in July from a parking meter where it was locked across the street from a busy HCMC clinic in Minneapolis.

Minneapolis police recovered 346 bikes in 2017 and 2018, according to department data. But recovered bikes often don’t come back in the same condition.

Auer, a 36-year-old whose 2017 Jamis Renegade XL bicycle is his primary mode of transportation, was one of the lucky ones who got his wheels back.

Auer contacted HCMC to get surveillance camera footage and alerted police, but he got little help. So he took it upon himself to scour online marketplaces and posted pictures on the Twin Cities Stolen Bikes Facebook group.

“I thought, if they are going to turn around and sell it, we are going to find it,” Auer said.

Group members help theft victims sift through online sales — and one of them spotted Auer’s bike. Auer contacted the seller and went with another group member to meet in a public place to buy the bike back. It had been stripped of its fenders, reflectors and other parts.

Since its creation over three years ago, Twin Cities Stolen Bikes has helped more than 100 people recover their stolen bikes, said Ted Duepner, one of the group’s administrators.

He said thefts may be rising because Minneapolis’ thriving cycling community means there are many high-end bikes on the streets and in garages.

“The risk to reward is unfortunately in favor of thieves,” Duepner said. “We’re totally invested in ensuring our community has resources if they’ve had a bike stolen.”

But he does not advocate meeting with anybody in possession of a stolen bike.

“Always call police to assist with a recovery,” he said.

Horn, of the Minneapolis Police Department, also said it’s best to call 911 rather than contact or confront a suspected bike thief.

Bike thefts peak from April to September, the most desirable months to ride. Police department data show the most reported thefts in downtown Minneapolis and surrounding neighborhoods where there are lots of bike commuters and students.

While most forms of transportation, such as cars and motorcycles, have to be registered, that’s not the case with bicycles in Minneapolis.

Cyclists can voluntarily register for free with Allard’s Project 529 or the Bike Index, another nonprofit online bike registry. There, owners can note a bike’s serial number, make, model and identifying features, and upload a photo. Locally, bicyclists are encouraged to register their bikes with the City of Minneapolis Bicycle Register Database.

If a Project 529 user’s bike is stolen, a tap of the app sends a blast to other members within 10 miles and shoots notifications across social media. Allard said Project 529 has 800,000 registered bikes in its database, including 8,000 in the Twin Cities.

Registration is one step, but Allard, police and groups such as the Minnesota Bicycle Alliance say riders can do more to protect themselves. Riders should use U-locks with hardened steel, typically priced at $50 or more. Cable locks are easily cut and compromised, Horn said. Riders should also make sure to lock up correctly through the frame and wheels to deter thieves, Allard said.

Auer said he was glad his community investigation prevailed. “If you are not willing to put in the leg work,” he said, “don’t expect anybody else to do it for you.”