Well lets look at a few comments made- Valk I hit the brakes and there was no difference so I doubt it was a brake problem. I do not see how a tire hanging in the air could develop flat spots. As far as cold tires, why wouldn't a car sitting out over night at below zero temperatures have the same effects when driving the first few miles. I have the stock all weather conti's on mine. Rapp's (Gary) you might be on to something. I'm just confused on why most folks who store have not had this problem and why mine the first 2 seasons of storage had not had it.