Originally Posted by jreeder
That's pretty close, but here is a better explanation:
http://auto.howstuffworks.com/question234.htm
Also, I'm almost certain that the only frame material that would have any effect on the inductance of the coil sensor is steel since it's magnetic. Al, Ti, CF... you're all out of luck.
Thats true, it would need to be steel. Hmm the only things steel on my Jamis comet were the spokes in the K elites, the chain, chainrings, and the cassette. Comparitively the Bianchi has the same steel parts with the exception of the spokes. Would steel spokes be enought to make the difference to set one off or not?