In February 2012 we had all the tyres on our 2007 Swift 590 (Fiat Ducato 2.3 base) renewed with Michelin camping tyres. The service this month showed a tread of 9mm on the spare, 8mm on both rear wheels which is fine but 5mm on the near side front and 4mm on the off side front. The wear is even so I don't think the tracking is at fault. This seems excessive as we have only done about 7000 miles since they were fitted and I was hoping to get about 30,000 miles out of them. At this rate we will be lucky to get 14,000 miles out of the front ones.