I don't think that's any kind of layer peeling, it looks like it could be cracking, or possibly the edges of where melted rubber was pushed inboard.
Edit: Pics from more angles might help, try your phone's macro mode.
Definitely not cracking, more like layers of an onion.
That looks like melted rubber that was pushed from the inside shoulder of the tire towards the center of the tread, that direction is unusual, is the car running a lot of toe-out?
In reply to CAinCA :
Yep immediately recognized the RT660 tread
I'm with Gameboy. Extreme toe-out.
On a track with a lot of right hand turns.
YMMV
Not alignment related but thanks for the input. Besides, if the RF was that far out of whack it would affect handling and transfer toe issues to the LF... but I threw some toe plates on it this morning to be sure and all is normal.
No big deal, this set of tires were carefully aged, fully-cooked, dry roasted and have become harder than Differential Calculus - ready for the scrap heap. But I've been running 200TW tires since they were 140TW and I've never seen that wear damage before... thought someone here might shed some light.
Just Falkens doing Falken things...
I have a whole bunch of bizarre-wearing RT660's pics that people have shared with me on my phone. It seems their quality control is not the best in the business. One set fine, next set not. YMMV, literally.