I have the BF Goodrich 245/45 ZR17's on. I've had them for a few years now and the tread is still in great shape cuz I rotate them every 5,000 miles. Everything felt fine before I did the rotation. Then after I did it I felt that "thumping" and it sound like it was right under my feet. I decided to rotate the tires back to where they were and I drove it to work today. Its fine again. No thumping at all. So I know the tires are good as far as the balancing is concerned. Im just thinking maybe its because of the treadwear until they wear down just a little more. That seems kind of weird but Im not sure what else it could be at this point. They are the rotational tires so they have to stay on the same side of the car when I rotate them. Like I said,right now the drive is smooth since I put them back where they were before. :-\