Investigations
FRACTURE OF THE STEEL WHEEL RIM
NHTSA Engineering Analysis EA04034 - closed, opened 2004-12-21.
NHTSA investigation EA04034 is a Engineering Analysis opened on 2004-12-21 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 2007-03-08 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
An Engineering Analysis like EA04034 is the deeper technical phase that follows a PE. NHTSA requests design, warranty, and field-failure data from the manufacturer, conducts its own testing when needed, and determines whether the evidence supports a safety defect finding that would compel a recall.
Investigators summarized the matter as follows: "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 VEHICL..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
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 DURING A HIGH-SPEED PURSUIT) MAY CAUSE THE CRACKS TO JOIN TOGETHER RAPIDLY. IF THE CRACKS ARE OF SUFFICIENT SIZE, THE STRUCTURAL INTEGRITY OF THE RIM MAY BE COMPROMISED RESULTING IN RAPID AIR LOSS AND RIM DEFORMATION. FOR POLICE VEHICLES USED AT HIGH SPEED, RAPID DEFLATION AND LOSS OF RIM STRUCTURAL INTEGRITY AFFECTS VEHICLE CONTROL AND MAY INCREASE THE RISK OF A CRASH. FATIGUE IS THE FUNDAMENTAL FRACTURE MECHANISM; THEREFORE, WHEEL FRACTURE CAN BE EXPECTED TO OCCUR (AND AT AN INCREASED INCIDE
About This Investigation Type
An Engineering Analysis (EA) is the in-depth phase following a Preliminary Evaluation. NHTSA engineers conduct testing, collect data from manufacturers, and perform detailed technical analysis to determine whether a safety defect exists. An EA may lead to a voluntary recall by the manufacturer or, in rare cases, a mandatory recall order.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.