What about larger profile tyres?
Seriously, I find this sort of error unacceptable or should I say deliberatly dishonest on the part of manufacturers.
With all the technology around surely these things can be made accuratly - after all the Police regularly say in Court that theirs' are accurate. So , considering they are making these statements under Oath, how do they get theirs to be so accurate yet we, who have to rely on them for our lisences, have to suffer such inaccuracies ?
The UK law requires speedometers to be accurate within + or - 10%
My own BMW F650GS-D speedometer shows a consistant 7 or 8 mph more than BMWs own SatNav supplied with the bike ! Double dealing here, or just a manufacturer out of touch wih what its riders want?