Had new tyres fitted all round about a year ago (Continentals bought from the internet, fitted at National Tyres) the tyres have been fab and all but one are still going strong after 20,000mls. however the front n/s tyre is showing wear on the outside edge. This wear was also evident on the previous set of fronts, so i asked National Tyres to check the tracking at the same time. They said they couldn't do it for these cars and it had to go to the main dealer. Does anyone one know what makes tracking an x-trail so difficult?