When I bought my bike off ebay it came equipped with a Polar CS100 wireless speedo but was missing the spoke magnet. I contacted Polar and they said that any powerful magnets would work (as I can't find replacement magnets anywhere). Having bought some miniature but strong magnets the computer still doesn't detect them despite moving less than 5mm across the sensor face. Does anyone have any other advice? Personally I don't see what was ever wrong with the wire connecting the two...it must have weighed at most 2g! But it worked!