"A YouTube video makes the case that Swiss superstar Fabian Cancellara might have won Paris-Roubaix and the Tour of Flanders this season with the help of an electric motor concealed in his bike frame. The charge is "mechanical doping."
See for yourself in the video's second half at about the 3:30 mark. It shows a Cancellara breakaway in both spring classics. Each time he motors off the front with unmatchable speed after moving his hand to the front of a brake lever -- the supposed location of a button that controls the hidden motor.
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An internal retrofit motor for the seat tube has been on the retail market since 2007 from Gruber Assist of Austria. It has a gear drive to turn the crank axle inside the frame's bottom bracket. The 22-cm-long motor is powered by a battery pack usually carried in a seat bag. Of course, pros don't race with seat bags."
http://www.roadbikerider.com/index.htm#NOTESEh...this thing sounds like a vacuum cleaner, and would be obvious to anyone riding next to him. Cancellara is a 3-time World Champion time trialist, and he really is just...fast.