I have just bought an ex demo 3008 4Wdrive hybrid. At 15000 miles the back wheel cord wore through and I ended with a flat. I have replaced both back tyres and the outer back is almost down to the cord. The fronts are both wearing on theinside. The tyre man says its because the 205/55/19 are not the right size for a car of this size. Any info. on this?