How to calibrate speedometer?
 

I am helping a friend install a speedometer in her 1994 E320 to replace her defective one. She bought exact same part number speedometer and had the mileage reset to match her actual mileage. Is there a need to calibrate this speedometer with her current tachometer or just install and go? Any ideas how to calibrate both if needed?

Just install it. it has already had the calibration that can be done.

Calibration is done on all but digital speedos by inputing a given frequency (revolutions on cable driven ones) and verifying that 60mph results (for mph speedos). The frequency or numbers of turns is written on the back of the speedo as K= or W=.

If this doesn't result in proper speed due to changes in tire size or gear changes then custom calibration is needed or a converter installed.

Thanks Steve. I was under the impression that you needed to calibrate anytime you replace either tachometer or speedometer. This one is not digital and doesn't have speedo cable either. just a couple of wires plug in the back of it.

speedo
 

It is electronic just converts it into an analog dial.