I think Henry is on the right track. Clutch explosion. I'm sure they will go over everything in the next few days to find exactly what happened.

I've heard stories of the cone causing the problem but KB in his report said he hit the cone with his back tire, and John won the race. So, that cone would have had to fly forward into a 315 mph breeze to hit john's car. I think the cone went behind john's car. I've watched that clip many times and everything happened very fast, but I think John's car is coming apart before the cone flies into his lane? I could be wrong.