Tires and Wheel Failure Analysis
The expert uses a ball and tape to measure the wheel to determine if the wheel used was the correct diameter for the tire that was mounted on it.
The Branick spreader enables the expert to perform a thorough tactile and visual inspection of the outside of the tire and inside the tire cavity.
An examination of the inner liner of the tire shows a large blister that could have been caused by either a manufacturing defect or puncture. The end result is tire failure.
An improper repair of this motorcycle tire caused the tire to begin leaking air again. The resulting low pressure contributed to the accident.
Often the question arises as to whether the tire failed before the accident or as a result of it. Tire failures can be attributed to a variety of causes, including:
- Manufacturing defect
- Improper repair
- Incorrect storage
- Installer error
- Prior damage
- Consumer misuse
In the investigation, the tire and wheel should ideally be examined as a unit. The wheel and rim may exhibit scuff marks, scratches, dents or wear marks that provide valuable clues in determining the cause of the failure.
Tire age has become a very important contributing factor in all types of tire failure, including passenger car, light truck and commercial tires. Aged tires are more susceptible to bruises and punctures; this damage is cumulative and can lead to failure, because an aged tire will not tolerate an impact that a new tire would sustain.
There have been new cases showing aged tires on the steer positions of school buses.
More wheels, both passenger and commercial, are being repaired, especially alloy wheels. In layman’s terms, the repair of an alloy wheel can weaken the alloy material strength, which can result in a tire / wheel failure.
The tire / wheel assembly should also be examined in the context of vehicle and scene evidence. For example, irregular tire marks can indicate that the tire was flat prior to the crash and not as a result of it.
Commercial vehicle tires fail due for the same reasons as those on passenger cars; however, there are additional areas that need to be examined. These include:
- Retreaded tires
- Heat buildup on dual tire assemblies
- Tire sidewalls that touch each other
- Worn out wheels and rims
- Service history/records for each tire / wheel
- Service history/records for the vehicle
Ruhl Forensic staff members have consulted and testified in numerous cases involving tire and wheel failure alleged as a primary or contributing cause of a vehicular accident.
Tires and Wheel Failure Analysis Staff
Edward C. Sebak, B.E.
Bachelor of Engineering
Gregory M. Wright
Heavy Vehicle Maintenance and Repair Specialist
ASE Certified Master Heavy / Medium Truck Technician