this just recently happened to me. once the belt flipped and the rubber was exposed, i asked myself if the cost of the belt is worth possible engine damage. i say this because my belt flipped and stopped turning my water pump fast enough and the temps pegged the gauge. i saw it and stopped the engine. how it didn't lay waste to the heads i don't know. this was a cloth Gates belt. to me, if the rubber is exposed it is trash!! Good Luck!!