Folks,
The speed showing on my sat nav matches exactly the speedo reading on my daily driver (E46), but the speedo on my beloved C3 always shows I am doing exactly 5 mph more than that same sat nav is telling me.
Assuming the sat nav and my C3 speedo are not faulty, could that exact 5mph difference be down to the speedo being set up for 15 inch wheels? The car has 14 inch wheels and always has as far a I know, or am I being thick here?
