I had a Trek insight 6i [$30] which I removed from my bicycle, the instructions explain how to calibrate it for any wheel,the pics show what ya need for your bike. The super strong magnets [$3] are at any craft store,[note:you need the super strong magnet to activate the sensor], some of that locktite gel glue, a few wire ties & you're ready to go. The sensor is wire tied to the brake bracket, the magnet glued to the disc. Run the wire from the unit/sensor any way you like. The unit snap slides out of the holder to take with you. Gives you mph/trip/time/etc. So far not affected by wet/cold. Runs on one of those little round batteries.

________________________________ ,,,,,,,,,,,,,,,,,,,,,,,,,, http://www.youtube.com/watch?v=u_WXxYGyRas Noli Irritate Leones