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!

Did you check your local bike shop?

Either check your local bike shop or buy one directly from Polar. They should sale them as they can be lost or needed for another bike.

Are you sure you got the magnet close enough? Most of the paperwork on the cyclometers are no farther than 2 mm from the sensor (on the line). I know that I had to put my sensor closer to the spokes to make for an accurate reading. I am using a Cateye Strada Cadence, but that is wired. The two wireless systems were the same thing on my wife's bike and I had to be even closer with my comfort bike with the cheap one.

Is the battery in the transmitter dead.

The magnet has to be very close to the sensor.

Also, where is the sensor mounted? Did you try taking the cs100 receiver off the bars and holding it close to the speed sensor?

If the above doesn't work let us know. I'll send you a few replacement magnets.

+1. Check the battery in the transmitter.

Um. No way to check the battery in the speed sensor. The unit itself is completely sealed and lasts about 2500 hours of use. Thats a lot of seat time.

if the battery is new.. is the head unit dead?