The message read: " As a side note, many new cars have an electronic speed sensor that uses rotation in the transmission final drive as the measured parameter, and then sends an electronic signal up to the speedometer. There is no mechanical link beteen the transmission and the speedo. Something like that has been discussed on this List in the past. I don't recall anything beyond the talking stage, however." As a backup, I've pondered adding a bicycle speedometer. The question is not so much where to mount the magnet but how to mount the sensor. Just a thought. Any input? Nick