FRACTURE OF THE STEEL WHEEL RIM

What NHTSA is examining

Fracture (cracking) of the subject vehicle (sv) wheel, which was previously investigated under preliminary evaluation pe03-009 (safety recall 03v-279), occurs in the model year (my) 2003 to 2005 police interceptor vehicles only; civilian specification and other my vehicles are unaffected by this condition.for the affected subject wheels, a fatigue crack occurs in the heat affected zone of the rim material adjacent to the circumferential weld that attaches the rim to the outboard wheel disc.the crack initiates under the outboard tire bead near the heel (where air leakage cannot be assured) and subsequently grows circumferentially through cyclic bending as the wheels rolls.although the vast majority of rim cracks either presented no symptoms or were detected safely via recurring slow air leakage, odi identified 6 incidents where rapid air leakage leading to a full or partial deflation of the tire was alleged.for these wheels, evidence indicated that multiple cracks had formed in different areas of the rim and subsequently grown together.two of the incidents resulted in a crash, one during a high speed pursuit.although the minority of cases, ford?s assessments of field return wheels showed that multiple cracks exist in approximately 17 percent of the cracked wheels replaced under a ford extended warranty program.in a wheel with multiple cracks, as the area between the cracks is reduced by growth a high stress condition (such as would occur in an aggressive vehicle maneuver…

Vehicles under investigation