I used a stripe magnet from a common kitchen refrigerator. I like these magnets because of the flat surface. Beware that these magnets have a magnetic face and a NON-magnetic face, so be sure to point the magnetic face outwards towards the sensor.
I cut two square or rectangular little pieces and glue them on top of eachother with locktite superglue.
To secure the magnet on the wheel braking rotor you can use a 2 component epoxy or the easiest way, locktite superglue. I've used superglue and the magnet never did com loose, but even if it did, I just cut another piece of magnet and glue it in place.
Easy peasy.
But please, don't go rip-off your wife's refrigerator door because I take no responsability :-)
Cheers
Ricardo
I am interested in fitting bicycle speedo on my b4 but how to you fit the sensor or magnet device on the wheel? On a bicycle it would fit onto the spokes so how can this work on a bike wheel?
I understand how they work but cannot figure out how to attach the sensor of magnet on the wheel itself. Obviously the other part can be easily attached to the fork leg or swing arm.