Speedometer adjustment?

[henryki]

Some people consider 195/60/14 stock size and I have seen many with this size when it is suppose to be 195/65/14. Po mounted 195/60/14 on my basket weave and when my speedometer showed 80mph, I'm actually doing ~72mph.

I'll double check my tire size. But when I know I'm doing 70 the speedometer reads 95

[vpilarrt]

the coding plug controls the tach and econogauge, it has absolutely nothing to do with the speedometer.

You're right, of course. For whatever reason when I first read the original post I was thinking of the tach and not the speedo.

[Gregs///M]

Was your speedometer ever swapped out? the speedo assembly must be matched to the correct speed sensor or you will be off. There is a calibration factor number printed on the face of the speedo and looks like this. k=xxxx with xxxx giving you a value.

[nando]

There are only 1 type of toothed wheel sensors - 9 pulses/rev. it's true that some will have different K-factors calibrated in though. given how crummy the components are I wouldn't be surprised if the output of the calibration could jump to a different value due to aging components. The resistors on these boards are like +/- 25%, a modern 10% resistor will really be more like +/- 5%.