Had a flat spot after all that straight road riding, but didn't look too bad 250 miles prior, then all of a sudden, belts were showing! Last Metz that will be on my bike! The no tread in the center is definitely deceiving!
BTDT. That's why it's been years since I have had a Metz or Pirelli Strada on my FJR.
I will say, that both the Avon Azaro and Mich PR2 you can ride several thousand miles *past* the wear bars without hitting cords/belts. Not that I would recommend doing that, or that those tires handle well, and could be an issue in the wet, but at least there are no 'oh ****' surprises. Nothing like that lump in your stomach when you see shiny stuff in the center of your tire when your still several hundred miles from home. BTDT. Didn't want the T-shirt.