[fingpilot]

Rick;

I seem to remember something about the steel belts (if they are steel) getting moisture as the tire rubber cracked with age, and rusting, causing the tread sep like that. How old are they? Maybe some kind of NHTSA search could come up with recall if there was one. You'd need the info from the sidewall. And a good tire guy/shop would gladly do the research knowing he was gonna sell you some new ones.