[alfa] Speedometer Calibration

["Dave Martin" <dwmartin@xxxxxxxxxxx>]

Dear Alfisti:
As Sir Smokey so rudely brought to my attention, my speedometer is, ah,
misleading.
I knew I was over the limit, but the number from his radar was way higher than
I thought I was going.
So I got out my handheld GPS and did some experimenting:
At indicated 55mph, Mr GPS says the car is doing 64mph
At  indicated 60, actual speed is 71mph
And at indicated 65, 79 mph - which agrees with Sir Smokey's radar.

I'll use this to try to get charges reduced to what the speedometer said, but
have any of you an idea why the speedometer is so far off?
The car is an '87 Spyder Quad, with stock rims (6J x 15" H2) and Owner's
Manual spec'ed tire size: 195/60 R15.
And what can I do to get it fixed?  Is there a gear in a sending unit that can
be replaced, or an adjustment screw somewhere?
Dave Martin
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