RIGHT FRONT WHEEL CAME OFF TRUCK WHILE GOING DOWN FREEWAY. THERE WAS A SLIGHT VIBRATION IN THE FRONT END ABOUT 10 SECONDS BEFORE THE WHEEL CAME OFF. THE LUG BOLTS WERE ALL SHEARED. THERE IS NO APPARENT WEAR ON THE WHEEL OR RIM. WE WENT OFF THE ROAD AND LUCKILY I WAS ABLE TO KEEP THE VEHICLE FROM ROLLING. HAD THIS BEEN ANOTHER MILE DOWN THE ROAD, WE WOULD HAVE MET A ROCK WALL AND SUFFERED SERIOUS INJURY TO PASSENGERS. *AK