Well, I was at the Hummer Happening we had locally yesterday and took a closer look at my tires. They had rotated the fronts to the rear last Friday. Looking closer this time, I saw that the inner part of the tread on the two tires was looking smoother than the rest of the tire. Not enough to replace the tires, but a little smoother, and only the very inner part, not center or outside. I have to wonder how it could have worn even that slightly since I've never felt any pulling right or left or experienced any wheel problems (other that rear grind I had been fighting with GM about) .. but this is the front.