Cycling-X-Ray Trucks to Be Used at Top Races to Detect Motors

[AngryScientist]

what a pathetic state of affairs though huh? to have illegal hidden motors even a viable concern.

[Mark McM]

Originally Posted by MattTuck

It would seem that the 3 things that you need for a motor: metal, battery and magnets, shouldn't be terrible difficult to detect.

There's lots of metal on a bike, so wiring may be hidden (and now that electronic shifting is possible, it may be easier to disguise or hide the motor wiring).

A battery could be hidden in the bottom of a water bottle (which can be easily removed and hidden before or after a race).

Some motors use electromagnets (instead of permanent magnets), so they wouldn't have a magnetic field when not energized. (And some motors use electric fields instead of magnetic fields, so may not show up on a magnetometer even when running.)

[MattTuck]

Originally Posted by Mark McM

There's lots of metal on a bike, so wiring may be hidden (and now that electronic shifting is possible, it may be easier to disguise or hide the motor wiring).

A battery could be hidden in the bottom of a water bottle (which can be easily removed and hidden before or after a race).

Some motors use electromagnets (instead of permanent magnets), so they wouldn't have a magnetic field when not energized. (And some motors use electric fields instead of magnetic fields, so may not show up on a magnetometer even when running.)

My memory of physics is a little rusty. Doesn't an electric field create a magnetic field that is perpendicular? I dunno, maybe they have super small shielded exotic undetectable motors designed by genius macguyver electrical engineers... but it seems like testing for the big things that are in most motors would be enough of a deterrence.

[Mark McM]

Originally Posted by MattTuck

My memory of physics is a little rusty. Doesn't an electric field create a magnetic field that is perpendicular? I dunno, maybe they have super small shielded exotic undetectable motors designed by genius macguyver electrical engineers... but it seems like testing for the big things that are in most motors would be enough of a deterrence.

Yes, a current through a single run of wire generates a magnetic field - but the field is much smaller than for a multiple loops of wire. (That's why electromagnets are made by using many windings of wire - each winding adds to the strength of the field). And the field can largely be cancelled by a twisted pair of wires carrying opposite currents, and the field can be nearly totally canceled by using coaxial wires.

Of course, if the motor is turned off, there is no current in the wires, and thus no magnetic field generated by the wires.

[adub]

Testing for motors is taking the same path as for PED's, they don't want the 100% foolproof way to catch all cheats..

[Mark McM]

Originally Posted by adub

Testing for motors is taking the same path as for PED's, they don't want the 100% foolproof way to catch all cheats..

Well yes, but finding hidden motors may be worse. For many, the use of PEDs is a grey area; some see it as merely a training shortcut, and the riders still have to pedal the bikes. But motors is very clear cut cheating, and makes a mockery of what is supposed to be a human powered sport. Another difference is that a rider taking PEDs is often explained away as an indepenent action by a single bad rider. But hidden motors takes a whole team - both the rider and mechanics have to know what's going on, so it is likely that the use of motors is a team conspiracy.