I just checked this on the net, it seems that, in Bridgestone's case at least, it is the heavy point. Cheers, Stu.I had the same problem with a Bridgestone Battlaxe, by rotating it 180 degs I was able to shed a bunch of balance weight. I then noticed a yellowish spot on the sidewall where the heavy point of the tyre was. Is this coincidence or is it a balancing mark? Cheers, Stu.