[MetroMPG]

In this case, the thumping is literally from a flat spot across the tread - the contact patch was dragged with the wheel locked (parking brake on), says the previous owner. You can clearly see the scrubbed down tread in one spot.

Either that or he spun out on the race track. I haven't decided which is more likely (I know he took the car to the track).

But good points nonetheless.

I guess I'm lucky - I don't think I've ever had a tire failure on all my (old, used) cars. The only time I've had to change a tire in the wild was when I slid into a curb in the winter (driving too fast for conditions) and popped the bead.