I just made two 400 mile highway trips in the last few weeks and I have a definite flat spot on the center tread of my tire. There is still plenty of life left in that tire and as far as I can tell, the squared offedness hasn't impeded my cornering much if at all. Sure, the tire doesn't look so pretty from behind anymore but it still seems to feel just fine when i get the bike leaning over. NOt as good as a fresh tire, I'm sure but I wouldn't say it feels hazardous or unpredictable. I still have a slight chicken strip and I haven't touched a knee yet but I work those corkscrews and cloverleafs pretty hard for a street vehicle. That bike sees some reasonable lean angles.
Just wondering if anyone would offer their opinions of center tread tire wear and how/if they feel it effects their cornering while sport riding. Thanks for your input.