Tread Seperation Information

Passenger and light truck tire tread separations are an unfortunate by-product of steel-belted radial tire technology. Due to the difficulty in obtaining adhesion of steel to rubber there is a potential for tread separation of all steel-belted radial tires. This is true especially at high speeds in hot weather. Industry records verify that tread belt separations are the most common mode of failure of steel belted radial tires. They result from both design and manufacturing defects.

The results of tread separation can be catastrophic. Tread belt separations frequently cause tire blowouts. Even when the tire does not lose pressure the driver loses control when the tread and belt separate from the carcass of the tire. These tread belt separations often cause vehicle crash and rollover resulting in serious injuries and fatalities. This problem is exacerbated by high-center-of-gravity vehicle designs such as employed in popular sport utility vehicles. The tire design problem can be overcome by use of a nylon overlay design modification known as “safety belts”, widely used in tires manufactured for the European market as well as many top line American tires. Manufacturing defects can be substantially reduced by appropriate adhesion, proper manufacturing practices, and adequate quality control measures.

When inspecting a separated tire you 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 also 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 wire surfaces as quickly after the accident as possible

Plant practices which contribute to tread belt separation include the use of over aged “dry” 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.

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