NEW YORK (CNN/Money) - The U-shaped steel bike locks that cyclists have relied on for years to keep thieves at bay just had a gigantic hole blown through their reputation, as bike lock maker Kryptonite scrambled to reassure customers that it is working on a solution.

The New York Daily News reported Friday that an Internet video has surfaced showing how to pick one of the most secure locks known to cyclists: stick the non-writing end of a Bic pen into the cylinder-shaped key hole and twist.

Although the trick apparently works on many locks with tubular cylinder technology including vending machines and some ignitions, it's the bike industry's best known locksmith, Kryptonite, that's feeling most of the heat.

Kryptonite said it will provide free product upgrades for certain locks purchased since September 2002 and urged consumers to visit its company's Website to learn how they can participate in the security upgrade program.

But only those who have purchased an Evolution lock, KryptoLok lock, New York Chain, New York Noose, Evolution Disc Lock, KryptoDisco or DFS Disc Lock in the last two years are eligible for a free product upgrade, the company said in a statement.

A recall of the flawed U-shaped locks -- a necessity for urban cyclists nationwide -- could cost firms tens of millions of dollars, industry experts told Reuters.

"I assumed it was a hoax myself but, unfortunately, a couple of us have done it here in the office with our locks," Leah Shahum, director of the San Francisco Bicycle Coalition, told Reuters. The manufacturers "need to replace these locks with locks that actually work."

The technique involves putting the back end of a plastic pen into the circular barrel of the lock and turning.

"This is not just a Kryptonite concern," a Kryptonite spokeswoman told Reuters. "This is an issue with some tubular cylinders, not all. Anything with a tubular cylinder could be a concern including vending machines, coin-operated machines, other security products."

A spokeswoman for Kryptonite's parent company, Ingersoll-Rand, said Kryptonite products account for less than 1 percent of Ingersoll-Rand's $10 billion in annual sales.

Dan Dacko, general manager of Planet Bike in Madison Wisconsin, said his firm, a smaller player in the U-lock market, was developing a plan to replace defective locks. But he did not know whether it would charge for such a recall.

"For a company of our size, it could be devastating," he told Reuters, adding that he had just received a shipment of thousands of the vulnerable locks.

He said the problem would likely affect European cyclists and firms as well as Asian manufacturers.  

-- Reuters contributed to the story