2004 HARLEY DAVIDSON, SOFT TAIL FATBOY. STOCK WHEELS AND TIRES. TRAVELING AT APPROX. 75 MPH ON I-8 ENTERING YUMA AZ. ALL 5 BOLTS HOLDING THE MAIN DRIVE PULLEY TO THE REAR WHEEL BROKE OFF. ONE BOLT FLEW BACK AND HIT ANOTHER RIDER THUS CAUSING MINOR INJURY TO THE LEG. NOT REPORTED. BIKE DID NOT CRASH BUT WAS DAMAGED. PULLEY AND WHEEL WERE TAKEN TO HARLEY DAVIDSON, THEY ARE NOT INTERESTED IN FINDING THE CAUSE. MANY MECHANICS HAVE LOOKED AT THIS AND HAVE NEVER SEEN THIS BEFORE. BIKE HAS 16002 MILES AND THE BOLTS WERE LAST CHECKED AT 10KMILES FOR 60 FTLBS. *JB