Separation Anxiety:

Basic Discovery in Tire Tread Separation Cases

By David A. Cutt, Esq.
David Cutt is a shareholder in the law firm of Eisenberg & Gilchrist where his practice focuses on complex personal injury and product liability cases.

Picture this scenario: you receive a call concerning an automobile accident in which the tread pealed off a steel-belted radial tire on the client’s vehicle. The ensuing rollover resulted in serious injuries. It sounds like a straightforward product liability case, because the tire is a simple piece of rubber which must have been defective if the entire tread detached. You file the case and request the usual product liability discovery such as test data, warranty claims, and information concerning other injuries and accidents.

Unfortunately, the defendant tire manufacturer produces little useful information and asserts that there has never been a problem with another tire of the identical model and size as your client’s tire which was also manufactured at the same plant during the same time period as your client’s tire. You notice up a Rule 30(b)(6) deposition of the tire manufacturer in hopes of gaining ammunition to support a motion to compel. However, the witness is emphatic that tires of different sizes, tread patterns, and load ranges are all distinct and unique products even if they share common components and experience the same mode of failure. The witness testifies that only tires of the same model and size manufactured at the same facility during the same time period are comparable products. Now what?

The reality is that steel-belted radial tires are complex products manufactured from numerous components through a multi-phase process. The tire industry is rather unique in its manufacturing, testing, and warranty products, and these complexities give the manufacturers plenty of obstacles to hide behind in discovery. Before you can hope to get anywhere in a tire defect case, it is essential to understand the various components of a steel-belted radial tire, as well as hoe the tires are tested, analyzed, and warranted. This article is intended to provide an introduction to the basics of discovery in a tire tread separation case.

A. What is a Tread Separation?
All steel-belted radial tires contain two steel belts which are stacked on top of each other inside the tire. (See Figure A). A “tread separation” or “tread belt detachment” occurs when the tread and outermost steel belt peel off the tire due to a separation in the rubber between the steel belts. In some cases, only a portion of the tread and outer steel belt detach, while in others the entire tread and outer belt peel off the full circumference of the tire. Tread separations were the failure mode which resulted in the mass recall of Firestone ATX and Wilderness AT tires which came as original equipment on Ford Explorers. If there is an automobile accident resulting from a tire failure, chances are good that the failure was a tire separation.

B. The Common Components of Steel Belted Radial Tires Steel belted radial tires are generally made of the same basic components which are depicted in Figure A. The components which are most important to understanding the issues in a tread separation case are the following:

1. Steel Belts

2. Skim Stock

3. Belt Wedge

4. Nylon Overlay or Cap Ply

C. Why Tread Separations Occur
Tread separations occurs due to a lack of adhesion between the steel belts, often as a result of defects in the design and/or manufacture of a tire. Achieving adhesion between the steel belts is one of the biggest challenges in designing and manufacturing steel belted radial tires for several reasons. First, rubber does not chemically adhere to steel. Therefore, the steel wires of the belts are coated in brass, and skim stock rubber surrounding the belts is specially formulated to adhere to brass. However the steel belts are cut during the manufacturing process, so there is no brass coating at the edges of the belts to bond to the skim stock. Moreover, there is a high concentration of physical stress at the belt edges because they are a natural hinge point between the stiff steel belts and the more flexible rubber side walls of the tire. As a result, the belt edges have high stress concentrations but low potential for adhesion to the surrounding rubber. Nearly all tread separations start at the edges of the steel belts.

Several components have been incorporated into the design of steel-belted radial tires to prevent tread separations by reducing stress at the edges of the steel belts. The most important of these components is the wedge, an area of thickened rubber placed between the belt edges. In addition, many steel-belted tires built in the last 30 years contain nylon overlays or cap plies which are pieces of fabric placed on top of the steel belts to further reduce mechanical stress at the belt edges.

D. Defects Which Lead to Tread Separations
As a general proposition, defects in the design and manufacture of steel-belted tires can result in tread separations due to inadequate adhesion between the steel belts. Examples of design defects include (1) specifying inadequate quantities of skim stock rubber between the steel belts, (2) specifying an inadequate belt wedge, (3) defects in the chemical formulation of the skim stock which result in premature deterioration and decreased strength, and (4) lack of nylon overlays or cap plies.

Examples of manufacturing defects include (1) lack of skim stock rubber between the belts or in the belt wedge, (2) degradation of components due to age, improper handling or storage, or contamination by moisture or other compounds, (3) inadequate “curing” of the tire, and (4) the use of an awl or other tool to pop bubbles which can form in an uncured tire.

E. Establishing “Substantial Similarity” of Various Tires Manufactured by the Defendant
One of the few certainties in life is that a defendant tire manufacturer will attempt to limit discovery to information concerning the precise model and size of the subject tire. The manufacturer is also likely to limit discovery to tires built at the same time period as the subject tire. Thus, the primary challenge in obtaining adequate discovery is to demonstrate to the court that numerous tire models and sizes built by the defendant are substantially similar. This will allow you to gain important information concerning defects and failures of a variety of tires manufactured by defendant and will greatly assist in demonstrating that the subject tire was defective.

A Rule 30(b)(6) deposition of the tire manufacturer is the best opportunity to gain the admissions you need to show the court that discovery should be permitted concerning various models and sizes of tires. First, ask the witness if a diagram similar to Figure A reflects the general design and components of all steel-belted radial tires. If the witness initially disagrees, further questioning concerning exactly how the diagram differs from the typical steel-belted radial will likely end the disagreement.

Next, focus on the components commonly involved in causing tread separations-the skim stock, belt wedge, and steel belt wire. The witness will verify the code number or other identifying information for each component used in the subject tire, typically something along the lines of the “M77 skim stock formula.” Next ask the witness which other tires built by the defendant used these same components. The response will often be that every passenger car and light truck tire built in the last ten years used precisely the same component parts.

It is also essential to explore the topic of “green tires” with the designated witness. The term “green tire” refers to the assembled components of a tire before they are put in a mold and cured. Tires are actually built by hand out of soft, sticky uncured rubber components. Before being molded and cured, the assembled green tires look very little like finished tires. However, the same green tire can be placed in different molds and cured into finished tires with different tread patterns and different information imprinted on the sidewall. Moreover, every tire manufactured from the same green tire shares the identical components. Ask the witness to identify all tires built from the same green tire as the subject tire, because there are certain to be others.

Once you have evidence that the defendant uses the same skim stock, steel belt wire, and belt wedge in more than one tire, you are well on your way to obtaining information concerning failures and defects in a variety of tires manufactured by the defendant. Your tire expert can provide the necessary testimony to explain that all tires which experience tread separations share a common failure mode,and that the skim stock, steel belt wire and belt wedge are the common components involved in tread separations.

Finally, ask the witness to explain how information concerning tire failures and defects is maintained by the company. Typically, you will find that information is stored in a centralized computer data base. Testimony concerning the ability of the manufacturer to cross-reference and access information on the tire failures, lawsuits, and warranty claims will enable you to rebut the inevitable objection that the requested discovery is unduly burdensome.

F. The Legal Test for “Substantial Similarity”
While it is necessary to show the court that the tires for which you are seeking discovery are “substantially similar” to the subject tire, the case law requires only similarity of the components which are allegedly defective, not of the entire product. In Smith v. Ingersoll-Rand Co., 214 F.3d 1235 (10th Cir. 2000), the court affirmed the admission of evidence concerning accidents involving several different models of milling machines other than the model at issue in the case. The court held that “the substantial similarity rule does not require identical products; nor does it require us to compare the products in their entireties. The rule requires substantial similarity among the variables relevant to the plaintiff’s theory of defect.” Id. At 1248.

In Whitehead v. American Motors Sales Corp., 801P.2d 920 (Utah 1990), the court held that information concerning products other than the one at issue was admissible based on similarity of the elements alleged to be defective. The Whitehead court affirmed the admission of films depicting crash tests of Jeep CJ-5’s in a case where the plaintiff claimed she was injured due to a defect in the handling of a Jeep Commando. The defendant objected on the grounds that the CJ-5 had a shorter wheelbase and different handling characteristics than the Commando. The court held that the test films were admissible despite these differences;

The requirement of “substantial similarity of conditions” does not require absolute identity; however, they must be so nearly the same in substantial particulars as to afford a fair comparison in respect to the particular issue to which the test is directed. The films here were offered to show the handling characteristics of the Jeep Commando. Plaintiffs’ experts testified at length that the handling characteristics of the CJ-5s shown in the tests and the Commando were substantially similar. Id. At 923 (emphasis in original). See also Lohr v. Stanley-Bostitch, 135 F.R.D. 162, 164 (W.D. Mich. 1991) (“plaintiff is entitled to discovery concerning accidents involving not only the stapler used by plaintiff but also other products that exhibit the features that plaintiff claims caused or contributed to his injury”).

The inevitable defense position that it need only produce information concerning tires of the same model and size as the subject tire is at odds with the legal standard for substantial similarity. The fact that two tires may be different models and sizes is irrelevant if the tires share the same components which your expert claims are defective or contributed to the tread separation.

G. The “Adjustment System”
One of the most important categories of discovery in any product liability case is information concerning warranty claims. The warranty system in the tire industry is somewhat unique, and a good understanding of how the system works and the applicable industry lingo is essential to obtaining adequate discovery.

The “adjustment” process is the tire industry’s term for the system of replacing tires which have defects or problems that are covered under applicable warranties. Under most manufacturers’ adjustment programs, a consumer may return a defective tire to a dealer, and the dealer determines whether the tire contains a defect which is warranted. If the tire is covered under warranty, it is deemed “adjustable,” and the manufacturer will take the tire and give the consumer credit towards the purchase of a new tire based on the amount of useful life remaining in the tire. In other words, the greater the tread life remaining on the tire, the greater the credit provided by the manufacturer.

Tires returned through the adjustment process are sent to the manufacturer and inspected by technicians. Detailed information concerning the nature of the failure or defect is entered into the manufacturer’s adjustments data base. Information from the adjustments data base is then reviewed and analyzed by the manufacturer’s quality control department as a means of monitoring performance and determining whether any problems in design or manufacture are leading to failures.

The defendant will seek to limit discovery to adjustment information concerning the model and size of the subject tire. However, in addition to demonstrating that adjustment data should be produced for all substantially similar tires, you should attempt to obtain Rule 30(b)(6) testimony concerning how the defendant actually uses its adjustment data. What you are likely to find is that adjustment data is reviewed and analyzed for failures such as tread separations for all models and sizes of tires. In other words, the manufacturers do analyze adjustment data for specific models and sizes of tires, they take a much broader approach and look for problems across an entire product line. This gives you the argument that sufficient adjustment data should be produced to allow you to conduct the same broad based analysis for tread separations as conducted by the manufacturer.

H. Testing and Failure Analysis
Tire manufacturers typically perform a variety of testimony and failure analyses which are potentially useful in demonstrating that design defects lead to tread separations. Knowing which tests are performed, how they work, and what they are called is important to gaining proper discover.

1. Durability Testing, Cut-Tire Analysis, and Holographic Analysis
Manufacturers test tires to the point of failure through durability, endurance and high speed testing. Reports are then created which describe the failure mechanisms, including tread separations.

Tires tested to failure are then subjected to either “cut-tire analysis” or “holographic analysis”. In cut-tire analysis, the tire is cut into cross-sections and the internal components are examined to determine if failures such as tread separations had initiated inside the tire without causing a complete failure of the tire. Holographic analysis uses a radiographic technique to create images of the internal components which are then analyzed for incipient failures. Review of data from testing and internal analysis is an essential part of analyzing a tire’s design to determine if it is likely to undergo a tread separation over the course of the tire’s useful life.

It is important to request documents regarding testing and analysis for both the subject model of tire and all tires built from the same green tire. Since all tires built from the same green tire are essentially identical, manufacturers will often test only one model built from the common green. The manufacturer will then claim in discovery that no durability testing was conducted on the subject model of tire, when the reality is that testing was performed on another model made from the same green tire.

2. Pull Tests or Wire Coverage Tests
Attaining adequate adhesion between the steel belts and the surrounding skim stock rubber is one of the most important aspects of tire manufacturing and is essential to preventing tread separations. Manufacturers regularly conduct tests for adhesion between the steel belt wire and skim stock which are known as “pull tests” or “wire coverage tests.” Belt wire is cured into blocks of skim stock rubber and then rapidly pulled out of the rubber to determine the amount of force necessary to remove the wire from the rubber, and the extent of rubber coverage remaining n the wire. If there is not adequate rubber coverage remaining on the sample of belt wire, then the entire batch of belt wire from which the sample was taken should not be used for tire production. Reports from pull tests or wire coverage tests on the batch of belt wire and skim stock used in the subject tire are potentially strong evidence of inadequate adhesion between the steel belts and skim stock rubber.

I. Nylon Overlays and Cap Piles
It is often alleged in tread separation cases that the subject tire was defectively designed because it lacked a component called a “nylon overlay” or “cap ply” which aids in preventing tread separations. Manufacturers routinely deny that nylon overlays or cap plies reduce the risk of tread separations. It is therefore important to obtain information concerning which tire models built by the defendant incorporate nylon overlays or cap plies, and to obtain testing reports, claims information, and adjustment data to demonstrate that these tires experience fewer tread separations than tires without nylon overlays or cap plies.

Information concerning tires which incorporate nylon overlays or cap plies is discoverable under a “safer alternative design” theory. In Walker v. Crown Equipment Corp., 353 F.3d 862 (10th Cir. 2003), the court held that under Utah law, a product liability plaintiff has the burden of demonstrating a safer alternative design to the product at issue. If the subject tire in a tread separation case lacked a nylon overlay or cap ply, then these components represent an alternative design. Testing reports, claims information, and adjustment data on tires which incorporate nylon overlays or cap plies should be discoverable to prove that the alternative design increases safety by reducing the risk of tread separation.

J. Information Related to the Defendant’s Claim of Comparative Negligence by the Driver
The defendant tire manufacturer in a tread separation case will often claim that the person operating the vehicle when the tread pealed off was negligent for failing to bring the vehicle under control. Many manufacturers have researched the issue of whether tread separations cause changes in vehicle handling which can cause an accident. All written, photographic or video materials related to the handling of vehicles following a tread separation should be requested, because you are likely to find that the manufacturer possesses information which contradicts its claim of comparative negligence.

Conclusion
Tire tread separation cases can be deceiving due to the presence of what appears to be an obvious defect in a seemingly simple product. However, tire manufacturers are adept at using complexities in the design and manufacture of steel belted radial tires as a smoke screen during discovery. In the wake of the Firestone recalls, there is a tremendous amount of information available on tire cases. With little research and networking, you can navigate the smoke and mirrors and get the documents and information you need to successfully litigate a tire defect case.