Wired Magazine have an online feature explaining the professional cycling tour’s fears of tiny motor assistance. In 2016, Femke Van den Driessche was banned from competing after being found guilty of "technological fraud" (using a concealed electric motor) during the Cyclocross World Championships.
Motors can be hidden inside a bike's frame - either inside fake water bottles, underneath the seat or inside the frame itself. Riders can activate the motors via Bluetooth by flipping tiny hidden switches in the handlebars. They may be tiny, but a tiny performance increase is priceless when we’re talking about conserving energy cycling uphill.
Electromagnetic wheels have been described by Italian newspaper Gazzetta dello Sport as "the new frontier of mechanical doping". The system works by using tiny electromagnetic coils inside the structure of the wheel to propel the bike.