Cheating in the sport of cycling has reached a "mind-blowing" new level, says 60 Minutes' Bill Whitaker. There's evidence that some professional riders are using bikes rigged with small, secret motors during races, a practice known in Europe as "motor-doping."

Whitaker and a team of 60 Minutes producers went to Budapest to meet Istvan Varjas, the engineer who says he invented the tiny bike motor, which he says has been used surreptitiously in the Tour de France.

What's more, Varjas says he's already at work on the next big cheating technology for cyclists: an electromagnetic wheel. (See how it works in the above video.)

An image of the magnet, in white, being placed into the rim of a bike wheel CBS News

Whitaker and 60 Minutes producers Oriana Zill and Michael Rey met the engineer in a bike shop in Budapest, where he showed the producers his inventions and allowed 60 Minutes cameras to film his souped up bikes in action.

"I didn't believe it before I saw it or heard it, but I'm totally convinced," says Whitaker. "You really cannot detect this thing, at least by sight or sound."

According to Varjas' design, a small battery-powered motor is hidden inside the frame of a bike and connected to the pedaling system with interlocking gears. When the motor is off, a rider can pedal the bike normally. When the motor is activated, it turns the crank, spinning the pedals for the rider.

Varjas says the motor can be activated in several different ways: The rider can activate a secret switch on the handlebars, a partner can activate the system by wireless remote, or a heart-rate monitor worn by the rider can be programmed to automatically activate the motor when the rider's heart rate rises to a certain level.

A small, battery-powered motor that can be hidden inside a bicycle's frame CBS News

Varjas told 60 Minutes he thinks professional cyclists have used secret motors to cheat in pro races as early as 1998. Varjas says he didn't knowingly sell motors for the purpose of cheating. He told 60 Minutes he just makes the device -- what customers do with it is "not my problem."

Now Varjas is developing the next generation in cheating technology using magnets to, literally, reinvent the wheel. He showed 60 Minutes a model of his latest invention, which appears to have small magnets hidden inside the rim of the rear wheel. Varjas says a battery and electromagnetic coils are also placed in the wheel. When the system is switched on, the electromagnetic coils create a magnetic field, which propels the magnets forward, spinning the wheel faster. Varjas says the system is silent, undetectable even to the rider.

Despite efforts to crack down on doping in cycling, the cheating story isn't over, says Whitaker. "It's like Whac-A-Mole," he says of the cheating problem. "You hit it down over here, it'll pop up over there."

The video above was originally published on January 29, 2017 and produced by Will Croxton, Ann Silvio, and Lisa Orlando. It was edited by Will Croxton and Lisa Orlando with assistance from Sarah Shafer Prediger, Rebecca Chertok Gonsalves and Susan Bieber.

Documentary footage from "Moteurs, ca roule!" courtesy of of Stade 2 - France Télévisions - report Thierry Vildary.

Bicycle animations created by David Rosen/CBS News.