VERY randomly the wheels/tires of my 2007 Forester (with 40,000 miles - over warranty, of course) will vibrate. There is no rhyme nor reason for when this occurs. The most regular occurance is first thing in the morning. The wheels (and I cannot say if it is front, rear or both) will vibrate - sometimes to the point where I pull off the road - and then this will stop and they will be fine. I may not feel it for weeks at a time, and then it will start again. I may feel it in the morning on the way to work, but not at all later in the day. The tires have 10,000 miles on them and have been rotated once. It just passed inspection so the brake pads are OK.