yup. actually not as dangerous as it looks. the rubber will melt, tho most of it will stay on and not really fly off as marbles being Land Mines on the track
what is more dangerous is when guys take their street bikes to a track day, burn the tires like this after a full track day with who knows how many heat cycles, then continue to run those tires back on the street - can you say just trying your luck to go down...
if you ever visit one of those bigger bike get togethers walking around, look at the tires and there's bound to be a couple there, showing off how cool theirs looks
It might be that the tire was under-inflated and as a result - overheated.
What brand/type, is it Michelin PR3? Is this your tire, or a re-post from another forum?
We call that marble. Usually if you drive off line, that's what happen. You can clean it up... it takes a lap or two. But if you drive in a corner and end up in those... bye bye! There's a reason why it's called marble. Any time you watch an oval race and see a car going a bit too wide end ending up in the wall... that's why. Once you pick up that crap you loose a lot of grip. I've scrape some of those with a heat gun and spatula before...
That's tire residue from racing compound tires that come off especially while cornering. Very annoying when accumulated. Like a very out of balance tire.
