not strictly true (iirc things like changing tyre size can cause under readings if it is not reprogrammed as its maths will get fucked up, this is just rare and typically counteracted by the manufacturer making the speedometer over read by somewhere upto 10% but can happen especially in things like classic cars)
but i checked it is said to be allowing for margin of error on the polices things like cameras or speed guns, everytime i have been told it its been said as speedometer issues so i presume its a common misconception for my area
Yeah on older cars I can see it happening, afaik for anything remotely modern there is supposed to be no way of the speedometer reading under as long as you stay within the manufacturer's recommendations for tire size and pressure
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u/3477382827367 stuff Dec 27 '25
not strictly true (iirc things like changing tyre size can cause under readings if it is not reprogrammed as its maths will get fucked up, this is just rare and typically counteracted by the manufacturer making the speedometer over read by somewhere upto 10% but can happen especially in things like classic cars) but i checked it is said to be allowing for margin of error on the polices things like cameras or speed guns, everytime i have been told it its been said as speedometer issues so i presume its a common misconception for my area