spontaneous fork failure without impact on a dry sunny street?? hmmm......maybe the OP should consider the possibility that something caused him to loose control before the crash, which then resulted in the broken fork...dunno, maybe he sneezed and lost control. i had a coworker who had a bee get behind his sunglasses, sting him and wham, broken collarbone. not saying the fork didn't snap because of fatigue but you have to consider other causes as well.