[Alpines] Speedometer questions

[Mark J Bradakis]

So we have this Alpine in the shop, Series V, I think (I'm a Triumph
guy, what do I know? )  The owner says the speedo reads too low,
following a car doing 55 mph his reads 42 mph, roughly 75% of
what it should.

It appears to have the original 3.89 ratio final drive.  It takes 4.25
revolutions of the driveshaft to make the speedo cable complete
one revolution.  The numbers on the Jaeger speedo are 5324/50 1020.

The owner claims that the speedo was redone by Nissonger recently.
The cable turns freely, no kinks, no binding.

Any ideas why the speedo reads so much lower?

mjb.