Cool! I wonder if it still works on the 'new' model?
As R7BKR says, there's 10% tolorence on the speedo dial...CDORISMAX said:However, the digital speedo is interesting. It is way out. i.e. Dial speed 50 mph. digital indication of 47mph. Which is correct? ( I don't, and never will, have a pratt nav. but might borrow one to check speed.)
I have more faith in the dial as often sit in the inside lane of our motorways with trucks which are limited to 56 mph. The speedo seems right then. does the 17" wheel make a difference?
In other words, to account for variations in wheel diameter, allied to the fact that it's illegal to under-report speeds but not over-report (to a point), the analogue speedo displays a slightly faster speed.Wikipedia said:Speedometers are not totally accurate, and most speedometers have tolerances of some 10% plus or minus due to wear on tires as it occurs. Additional sources of error are tire diameter variations due to temperature, pressure, vehicle load, and nominal tire size....
...As with the UNECE regulation and the EC Directives, the speedometer must never show an indicated speed less than the actual speed. However it differs slightly from them in specifying that for all actual speeds between 25 mph and 70 mph (or the vehicles' maximum speed if it is lower that this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph.