Hi all I'm the very proud owner of a 1985 Mini City 1450cc and I'm suffering
from the problem of an incorrect reading Speedo, The car is sat on 13"
superlites with Bridgestone Potenza's now as far as I can tell from
stripping the gearbox down the Speedo drive runs of the main shaft so is
directly related to engine RPM.
The things I think come into the equation are RPM, Diff Ratio, Tire Diameter
and Speedo Drive Ratio.
From this do any of you have any experience of a similar setup and can put
me on the correct path for what Speedo drive I should be using to get close
to the correct indicated speed on my new 120MPH 3 dial clocks.
Or know of any electronic Speedos on the market that use some sort of drive
shaft sensor.

Thanks
Karl.