A grueling cycling race is somewhat less grueling if your bike is a motorcycle. Understanding this, some cunning cyclists may be turning the sport into Nascar on two wheels by surreptitiously giving their bikes a motorized boost.

The first confirmed case of mechanical doping surfaced this year when a tiny motor and battery were found inside a Belgian cyclist’s bike, but that involved cyclocross, a comparatively minor branch of the sport. The latest accusations emerged Sunday on Stade 2, a sports program on the French television network that is also the host broadcaster of the Tour de France. The report suggested that motor doping is also at the highest levels of the sport.

Suggestions that top riders are rigging their bikes have escalated in the past several years. As was the case in the early 1990s with more conventional doping, riders who are the targets of such accusations have dismissed them.