[jyl]

I'm finding the whole idea of building an undetectable motor into a bike just very interesting.

The UCI started out physically disassembling bikes (remove crank, use probe camera to look inside frame). They also started bringing portable xray machines to races. At the CX Worlds, they used a new "tablet app" to "scan" the bikes, any flagged as suspicious were disassembled. I think the app was an EMF detector, that uses the tablet's magnetic field sensor (enables the internal compass and attitude measurement) to look for the magnetic field from a motor's permanent magnets. Those sensors will also, I think, detect sufficiently large amounts of ferrous metal.

The existing internal motors (Vivax, Typhoon), which fit in the seat tube and drive the crank via a worm gear, would be easily detected with such a scanner. The Typhoon company actually helped the UCI develop the app. Then removing the seatpost would reveal the motor (and battery, if concealed there) and removing the crank would reveal the worm gear.

But the motor could be a type with no permanent magnet, I think. Use coils on both stator and rotor. And perhaps such a motor could be with no ferrous components, using copper windings, aluminum parts, ceramic bearings, some sort of plastic or fiber gear. So that might elude the scanner.

Then the battery could be hidden in the downtube. LiPo battery packs are small, light, and powerful. And we could fill the seattube with a Di2 shifter battery. So now, removing the seat post won't immediately reveal the motor.

Hmm, what to do about removing the crank? I can't think of a way to fool that test.

The motor-in-the-rim idea that I initially asked about was inspired by a newspaper article. An Italian reporter was told by someone, who claimed to build concealed bike motors, that hiding motors in seat tubes is so last decade, the state of the art for motor doping in bike racing is $200K "electro magnetic rims". So I started thinking about if this is really feasible. So far, I think "no" and the reporter got snowed. But I'm still thinking about it.

Anyway, any "rim motor" that uses magnets in the rim will be detected by the UCI's scanner too. And by simply lifting or spinning the wheel.