Hi again, I'm not sure what the problem is exactly. The only theory that Subaru has is that tires of different sizes will cause this kind of wear. I got the car with 70K on it, at that time it had four brand new tires, all exactly the same size. Since then I have replaced the tires, all four at a time, once with a set of Perellis, and just two weeks ago, with a new set of Toyos, again all exactly the same size. I have never had a flat tire, so I have never driven the car on a "donut" tire, the spare hasn't ever been on the road at all!
It seems to be one of those "who knows!" kind of deals. I like Subaru a lot, and the all wheel drive is great, but when it breaks, WOW!
larry.k