I've checked this against a few peoples cars now, and it seems that the Speedo on my cav is reading above what it should be. I.e when at 70 it reads about 76ish, and at 60 reads 65-66. I haven't checked it at lower speeds so I am assuming it is the same lower down.

The car is standard at the moment so the calibration of the speedo and everything should be right. Does anyone have any ideas how to check it properly, or possible causes of this. Are there any solutions, or should I wait till I get alloys and just put tyres with a bigger rolling radius on.

Cheers