Ahh... thanks. Mostly it is the indentations you refer to, and they are somewhat regular. However, there are some bulges which appeared after a couple year's use, and hard use it was at times! I suspect my last trip into Death valey is the culprit: loaded with passengers and gear, miles of washboarded and potholed gravel/dirt road, speed about 25mph. Maybe next tires should be 6-ply.