Tire Failure Examination

The examination of the tire in great detail in a laboratory with several days of photography and introspection is necessary to find the small items and put the entire history of the tire disablement together. Field inspections, while sometimes necessary, generally result in the determination of the cause away from the tire while comparing notes and photos taken while at the inspection site. Discovery evidence can help put detail together or in perspective but it is always the tire examination that is the crucial part of the case. Therefore field examinations, while expedient, are never as good as having the time, lighting, and tools of a laboratory. Field examinations should be followed by laboratory examinations prior to testimony being given. Here is a case in point.

The tire arrives after having been examined by the other side in their laboratory. The claim being made is that the store that saw the vehicle (not necessarily the tire) 10 days before the accident should have known that something was amiss with the tire since they saw the vehicle. In fact, there is discovery material that the tire was not inflated to its rating as listed on the vehicle placard. The evidence indicates that inflation pressures 50 to 60% of the placard pressure had been put into the tire and the loading could have been up to 100% of the design load. An examination of the tire indicated from all the potential overdeflection evidence that the tire could not have been 50% underinflated considering the loading that was found during discovery. There was overdeflection in the tire but 50% would have created far more evidence as seen in the tire. In addition, there was a strong indication of ICP (Intra Carcass Pressurization), however the split through the innerliner that existed in the tire casing at the belt separation definitely happened after the de-tread since the crown area of the bottom belt contained "Road Rash". Therefore this area with the liner split was not the cause of the ICP and there were no other indications upon first examination of a liner breach in the field. After the initial field inspection was complete and some time had passed, a very close examination in a laboratory, of the interior shoulders found two small innerliner cracks that had not been noted by opposing experts. These two small liner cracks that were open to the body ply cords were the cause of the ICP and the root cause of the belt separation and tire disablement. Finding the cause of failure as two liner breaches and the lack of 50% overdeflection evidence in the tire resulted in settlement.

To see the resume of the expert associated with this case study, see the link below.