Fixing a Speedometer??

Slantsixdan I don't want to sound like a know it all but... I looked at the way speedos work. You are right they spin magnetics which create eddy current this current is measured by the mechanical speedo and the gauge is moved. The link below explains what I am reffering to. We are technically both right I just didn't address the spinning magnetic part.

http://www.explainthatstuff.com/how-speedometer-works.html