Steel-belted radial tires have been an amazingly reliable technology that has lasted for decades. The concept is fairly simple – design a container that is flexible but durable, holds in a highly-pressurized amount of air, and use that to suspend a heavy load so it can move, i.e. a car. However, as tires developed, the manufacturing of tires involved more and more ways of layering rubber onto steel radial versus fabricating it as one unit. These layers are adhered together in a high temperature process, squeezing the radial in between.
Unfortunately, the actual design of a radial tire is also its weakness; the layering approach creates an inherent weakness for separation. This typically occurs when a car is going at very high speeds, which already heats up a tire, and is doing so in hot weather areas, like a desert.
Statistically, the most likely failure for a steel-belted radial tire is now a catastrophic failure due to tread separation. This is where the outer layer with all the grooves one sees on tire literally peels off the tire body itself. No surprise, the inner layer cannot survive long against the pavement and fails as well, eventually triggering a blowout and loss of vehicle control. A number of different tires have had tread separation occur, whether it be on trucks, SUVs, or vans.
Tread separation across all affected brands has shown to follow specific patterns. First off, it happens predominantly in warmer climate regions versus cold. Second, underinflation seems to augment the condition, triggering it to occur faster. Third, it is not a brand-specific problem. It is a design-specific issue.
In almost all cases, when tread separation has occurred it has eventually lead to blowout of the tire itself. The inner layers and loss of radial are too weak to maintain the typical tire pressure as well as contact with the road. The vehicle is also extremely hard to control when this occurs, particularly at high speeds, and it results in accidents with injuries and death. With cars that have a high center of gravity, such as trucks, vans and SUVs, the problem is worse, often resulting in rollover situations.
Understanding that the actual design contributes to the issue, tire manufacturers have since been trying to craft a way to keep the design but make it safe. This has included increasing the adhesion between layers, changing the production process, and improving unit production processes such as rejecting old rubber stock. It has been found that tread separation can be the result of rubber that past a prime age, allowing solvent exposure, allowing contamination to occur during the curing process of a new tire, poor inspection, and ignoring known safety procedures in production.
The liability of tire manufacturers has been established again and again that tread separation was avoidable and preventable. Further, not only has negligence been an issue, companies have been found to intentionally try to cover up issues from their own inspections as well as external ones, misleading everyone involved and the consumer for the sake of production and profit.
A number of symptoms will show signs of improper production when tread separation causes a tire failure. For example:
- Corrosion on the tread wire likely signals moisture contamination during the curing process.
- Bare tread altogether can mean that the adhering of the layers failed and did not embed into the tread.
- Brass colored tread also signals failure of adhesion during curing.
- Obvious contaminant presence in the tread such as metal, objects, non-tread wire and other objects.
No surprise, with these kinds of symptoms, getting high definition photographs of the suspect tires is critical as soon after the accident as possible. The longer the time passes from the accident, the more such conditions can be explained away by exposure and compromise of the evidence involved.
Tire manufacturers and car part retailers who sold the tires will immediately look to blame the driver or road conditions as the cause of a tread separation. However, case law and repeat research has well established design as a major cause.