Automobile Wheel Lug Nuts Accident

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 had been improperly tightened.  After one month of driving, the wheel came loose from the automobile and a one vehicle accident and personal injury resulted.

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Photograph A: Overall view of wheel which separated from the axle in a one 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. 

Photograph B: Close-up view of axle plate and wheel studs. Note three of five wheel studs are present. Two wheel studs failed by metal fatigue. The two wheel studs that failed by metal fatigue are denoted with white arrows.

The automobile wheel rim lug holes were completely "wallowed" out of round 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 automobile.

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