If you've ever modified a car with smaller or larger tires or, perhaps, a different final-drive gear, you've immediately screwed up your speedometer. This is, of course, annoying, but for modern cars ...

It's a problem many may not know they're experiencing until flashing lights in the rearview mirror tell them otherwise. How do you know if your vehicle is reading an accurate speed? And if it isn't ...

From '65-'93, Mustang speedometers were cable-driven mechanical instruments that worked on the eddy current principal-a magnet whirling around inside a shell attached to an indicator needle. The ...