Speedo Accuracy

[Chuck2]

Can anyone tell me how accurate the GC speedos are.

Fitted a bigger set of tyres & want to see what I have to allow for.

On my D4 the speedo was six km/h out i.e. reading 100 at 94

Thanks for the assistance.

Cheers

Chuck

[skipperau]

Originally Posted by Chuck2

Can anyone tell me how accurate the GC speedos are.



Fitted a bigger set of tyres & want to see what I have to allow for.



On my D4 the speedo was six km/h out i.e. reading 100 at 94



Thanks for the assistance.



Cheers



Chuck

Best way to know is compare the speedo to a gps. Get on a long straight and hold a given speed and compare the 2. Take comparisons at 50, 60, 70, 80, 100, and 110 kph, that way you will know exactly what to expect, they can vary from unit to unit, as well as speed to speed, eg. 4kph over at 100, but only 2kph over at 60. There are modules that can be wired in to adjust for tyre size differences too btw, so if a tyre is 8% bigger for example, you program it to read 8% higher so you Speedo is accurate with those tyres, good if you intend on keeping that size, a bit of a pain if you change sizes regularly.


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[NickT]

Going by the GPS my WK2 is just 2KPH out out at 100, so it is very close. My VW Golf is 7KPH out at the same speed.
Nick

[Chuck2]

Went for a drive this afternoon and used a phone passed speedo app & the same sort of results.

2km/h out at 100 on the speedo
1 km/h out at 60 on the speedo

This was with new BFG AT KO2 in 275 65 18.

Cheers

Chuck

[MexicanBatman]

Mines 2km off at 100km/h but I’m using SRT wheels and Tryre size

The VSS shows the exact same speed as GPS

[Numb Thumbs]

I'm on stock 18" tyres and the speedo is out by around 2% compared to three GPS's, driving on the flat in a straight line - shows 101 or 102 at an actual 100 by GPS.

Cheers
Numb Thumbs