accuracy of our speedo

[PeterHBne]

This is what I do. Get your trip computer to either the 1 or 2 setting (depending on whichever you don’t care gets reset often). Go to the average speed option. Pick a speed - say 100KMH indicated, hold on cruise control then reset the average speed setting using the reset button on the stalk and it will give you an accurate KMH reading. I find invariably, as mentioned elsewhere, indicated 100kmh is about 92-94kmhs actual and 110 indicated is about 102 actual. After a while you will get to learn what your actual speed is against indicated.

[Bubu]

I used a GPS (non industrial) to calibrate the speed on the Scanguage. Now I dont even bother looking at the speedo I just go off the readings of the Scanguage.

[nomodlowkmgti]

What rpm on the tacho is 100 gps speed maybe you can use a rev speed in 5th if it points to a mark as a way to do 100 real speed or is each polo a bit different.may be a formula to do with diff and 5th gear ratio x rpm to = 100.