After I finally got tired of moving my spoke magnet from one wheel to the other every racing weekend, I went and bought a generic spoke magnet. Big chunky barrel shaped thing. I put it on and adjusted the gap, then spun and spun the wheel - nothing, no pickup. I checked that it is actually magnetized - that's fine. So what gives? Is Polar just 'special' and requires proprietary spoke magnets? Mine is the CS200cad, btw... Thanks!