bazza1966

So is the TomTom speed reading the most accurate indication of my actual speed? As it's measured by the GP Satellites.

I have recently upgraded to 17" rims from the original 16" ones on my IS220d. On a recent trip to Leeds I noticed, where the distance had always been 177 miles door to door before, it was now 170 miles. I do realise this is to do with the slightly bigger turning circumference, approx 6cm, in the rear 245/45 R17 wheel/tyres in comparison to the original (ugly) 205/55 R16s. My question is which is the more accurate? I am thinking possibly the 17" rim mileage, as I also noticed my speedometer speed more closely matched the speed on my TomTom compared to before, where it always seemed that tad faster.

Has anyone got any idea of the latest edition Great Britain sat nav cd for a '00 registered is200? I currently have the '03-04 (Apr 2003) version. cheers