For some reason the speedometer in my Focus seems to be wrong when I go above 20mph. I noticed it when I first used my sat nav and for some reason my speedo says I'm doing about 5mph faster than the sat nav. I'm assuming the sat nav is more accurate? Double checked it with a mate on the motorway in his clio and he said I was doing 65 when my speedo was saying 70.
Is there an easy way to maybe reset/recalibrate the speedo? It's not a major issue, and if anything it might help me avoid some nasty speed cameras, I'd just prefer it to be right.