Automobile Wheel Lug Nuts
A Ford automobile was taken to a garage for a brake pad change. When the rear wheel was replaced, the lug nuts which hold the wheel in place
improperly tightened. After one month of driving, the wheel came loose from the automobile and a one vehicle accident and personal injury resulted.
Photograph A Wheel which
separated from the axle in a vehicle accident.
Metallurgical failure analysis revealed that two of the five wheel lugs failed by
metal fatigue. The lug nuts from the three remaining wheel lugs totally backed off allowing
separation of the wheel from the automobile.
View of axle plate and wheel
The automobile wheel rim lug holes were completely
wallowed out from their round shape during the one month driving time.
Photograph C Close-up view of wallowed out wheel
stud hole in wheel rim.
The automobile accident occurred as a result of the rear wheel lug
nuts being improperly tightened, allowing the rear
wheel and tire to come loose from the subject