Olympic time-trial champion Fabian Cancellara on Tuesday rubbished claims that he used a 'motorised' bike when winning this season's Tour of Flanders and Paris-Roubaix classics.
"It's so stupid I'm speechless," he said. "I've never had batteries on my bike."
A video featuring former professional cyclist Davide Cassani seemingly showed a bike operating with what he claimed was a motor concealed by the pedals, with a button to operate the device hidden on the handlebars.
In Cassani's video, there is footage of Cancellara and what it claims are suspicious slips of his right hand on the bike handlebars before he acclerates effortlessly away from his rivals.
"It's quite funny but it's become a bigger story and is no longer so funny," said Cancellara. "It's a sad and really outrageous story. Believe me, my feats are the result of hard work."
In both races, which are held in April, the main casualty of Cancellara's stunning accelerations was Tom Boonen - a former three-time winner of Paris-Roubaix and former Tour of Flanders champion.
But the sport's governing body, the UCI, confirmed that there was no case against the Swiss rider. And the UCI's technical chief, Jean Wauthier, told Belgian daily newspaper Het Laatste Nieuws that it was unlikely Cancellara would use any kind of motor.
"The risk is simply too big. For him, his team and the bike manufacturers. A champion like Cancellara would not take that risk."
Wauthier admitted that even if the UCI wanted to, there was no way of checking whether Cancellara had cheated by using a motorised bike. However he admitted the sport's governing body had, like Boonen, perhaps been caught napping.
"If there's been some kind of fraud, there's no way of proving it," Wauthier said.
He added: "Certainly we're going to have to speed up our research so we can scan all competition bikes in a quick and efficient way. Up till now, such controls simply haven't been used."
Under close scrutiny the Youtube clip is almost believable.
But while Boonen's sports director Wilfried Peeters said he had to believe Cancellara, team manager Patrick Lefévère called on the UCI to investigate the claims fully.
"The film on Youtube does make you doubt," Peeters, the Quick Step sports director for both races, told Het Laatste Nieuws. "But I'm convinced Fabian achieved his feats using his own means."
Lefévère added: "I was a bit circumspect watching the clip. But if we imagine it's true, it's daylight robbery. It's worse than
"I don't want to get involved in all these rumours and I'm trying not to get paranoid. But after seeing this video I hope the UCI are going to fully investigate."
UCI official Wauthier meanwhile admitted the sport's ruling body have had to "amend the regulations to ban the use of such bikes in competition" after the new technology emerged around 2005.
But the UCI said they are now faced with another problem.
"Today we're confronted with bikes that can run on batteries. But we also know that similar mechanisms, that work without batteries and can run on solar power, are being developed," said Wauthier. "We will have to get for that challenge too."
© AFP 2010