A third guideline is that the speedometer pointer, or needle, be near the 12 o’clock position when driving at the maximum normal speed, say 65 mph.

Classic Instruments gives us a look at how to calibrate an off speedometer using their Zeus Speedometer Technology (ZST), makeing the process a simple one.

Have you changed your tire size or final-drive gear? You just made your speedo and odometer inaccurate. Here's how to fix them both.

The speedometer pointer will drop to 0 and the calibration is stored. Remember that the accuracy of the 2 mile distance will directly affect the accuracy of the speedometer.

Felix says tyre pressure, the brand of tyre, the thickness of the speedometer pointer and even the height of the driver can affect speedometer accuracy.

The face is white with black old-fashion-style numerals and pointer; the bezel is polished stainless steel. The tachometer and speedometer are the same size, 3⅛-inch case, and the other gauges ...