I flipped a GPA211, after 4 sessions (at my slow A pace) the horizontal seam opened up. I had what felt like a big sideways step out so I pulled in to see what was up, that's when I saw the separation in the tread. I saw two other tires that same day with similar faults...all on flipped 211 GPA's. Now, it was really hot that day so temperature was probably a contributor. Would I do it again? Yeah, just pay attention and inspect your tires after every session, which you do anyways, right?