A rogue 200 pound truck wheel bounding toward your windshield is the stuff of nightmares. These highway missiles can roll long distances and bound 15 feet into the air. An especially dangerous scenario is a truck wheel that bounces over a divider separating the opposing traffic lanes of an interstate highway. Another, is a wheel-off occurring in an urban area, which endangers road traffic and pedestrians on sidewalks. The wheel of a semi truck or its trailer can come off when the wheel bearings fail. However, a common reason is incorrect wheel.