Speedo accuracy

[AWo]

At least for Germany I think that is fully legal and quite normal. A 10% difference is fine, as long as the measured speed is higher than the real speed. The other way around is not allowed.

You need to check the speed and maybe adjust it, when you mount wheels with a larger diameter, as that speeds up the car while measuring the same speed at a given RPM.

With 5% lower I wouldn't worry about.

AWo

 

[Jeremy996]

The rules for the UK, (and still for EU), are never over the true speed and up to 10% under. If you change wheels and tyres, it is your responsibility to ensure that you still comply.

How you would recalibrate the Grenadier's speedo is anyone's guess at this time!