Manufacturing Defects.
Manufacturing defects can be substantially reduced by appropriate adhesion, proper manufacturing practices, and adequate quality control measures. Some plant practices which contribute to tread belt separation include improper curing, the use of over aged "dry" rubber stock, use of petroleum solvent on tire components prior to vulcanization, moisture or foreign matter cured into the tire, improper repairs, inadequate final inspection and an emphasis on production or quantity over quality and safety. Many plants run on twelve-hour shifts with the tire builders working on a quota incentive system which unduly stresses workers.
When examining a separated tire one should look closely at the separation interface to determine whether there is any rusty wire, bare wire or brassy wire exposed. Corroded wire is usually evidence of moisture contamination during manufacturing. Bare wire is an indication of a manufacturing adhesion defect. Brassy wire is a strong indication of no adhesion. High resolution photographs should be taken of any exposed surfaces as quickly after the accident as possible to document any exposed wire conditions and the condition of the surface where the tire has delaminated.
Underinflation and Impact Damage.
Traditionally, the tire industry has attempted to shift the burden for defective tires to the victim in the accident. They assert that tread separations are the result of impact damage or underinflation. In fact, underinflation does not cause tread belt separation in a properly constructed, properly designed tire. However, if a tire has manufacturing or design defects and it is run underinflated, underinflation can accelerate tread belt separation.
Unfortunately, it is virtually impossible for the consumer to determine whether a steel belted radial tire is underinflated by visual inspection. It is often difficult, if not impossible for people who are forensic tire experts to determine upon visual examination whether a tire has incipient tread belt separation prior to the actual failure of the tire that causes the steel belt(s) and tread to separate from the carcass.
The potential for underinflation is increased by the air permeability of steel belted radial tires. All steel belted radial tires leak air. Design and manufacturing defects can accelerate this leakage rate. Because of the air permeability of steel belted radial tires almost all tires are run underinflated at some time during the course of their lifetime and, as noted, this is usually not observable by the consumer. Accordingly, the victim is usually unaware that the tire is underinflated and certainly unaware that underinflation will result in tread belt separation. Likewise, impact damage does not cause tread belt separation. Impact damage can cause failure of a tire, but it is not a tread separation failure.
Tire manufacturers often claim that damaging information contained in their records is trade secret and should not be disclosed. The truth of the matter is, comprehensive analysis of steel belted radial tires is reported to tire manufacturers by Smithers Scientific Services so that all of the tire manufacturers are routinely provided with the physical properties and chemical makeup of their competitors’ products. Tire manufacturers also reverse engineer their competitors’ products on a continuing basis and are well aware of the composition of tires manufactured by their competitors. They purchase raw materials and tire manufacturing equipment from the same vendors. Accordingly, there is very little bona fide trade secret information that is not known by all tire manufacturers about their competitors’ tires. They all build tires essentially the same way with essentially the same equipment. Tire manufacturers also occasionally build tires for their competitors under the competitor’s brand name.
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