I have a 2012 3.0d X5 from new. Its done 20000 miles in 18 months. I have 20 inch Dunlop SportsMaxx. My first set of tyres lasted 5500 miles. My second set lasted 4400 miles. I had the tracking checked etc and all OK. Tyre pressures monitored regularly. I drive 'normally', that is, I do not thash it. My local BMW service dept are at a loss as to why the tyres go so quickly and have suggested running with slightly more pressure. Any ideas?