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For the record I have just calibrated the digital speedo against GPS and it is more accurate than most Japanese or Italian ones.

At an indicated 70 mph true speed is 68 mph. So it over reads by less than 3% which is pretty good.

The figures were collected on a long continuous run trying to maintain 70 indicated throughout. The recorded GPS track was then examined to obtain true actual speed and in several stretches this was maintained for more than two miles.

The error is likely to be proportional ( so for example a true 100 should read 103 ) but I am not likely to be able to verify that any time soon.

I will be hooking up an independent digital tacho at some point so I'll be able to verify speed vs. RPM in gears soon.

Regards Roadster
 

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I tried my Garmin 60 yesterday on the EXC as well as my iPad with the HEMA App, the GPS was about 15km/h slower than the bike and iPad app readouts so Im not sure which ones lying. Will mount them on the Duke and try again on open road instead of dirt roads.
 

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In Australia most speedometers read high because of ADRs (Australian design rules ) . From 2006 ADRs say a speedo can't read below the actual speed but up to 10% + 4 kph high . So products speedometers sold here seem to read on the high side to cover there arses :)
 

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Glad to hear the speedo is accurate because I have heard that other bikes purposely make the speedos inaccurate to prevent people from speeding as fast. I've always thought that was a slimy practice though.
 
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