WASHINGTON—Nylon cap plies are either a vital safety feature tire makers have left out of the construction of many of their products, or else an optional feature unnecessary on tires that aren't speed-rated or designed for ultra-tough conditions.
These are the stories proffered by plaintiffs' attorneys on one side and tire makers on the other. Normally, except in the context of specific tire-related lawsuits, it's not a question that concerns the general public. With the Bridgestone/Firestone Inc. recall of 6.5 million tires, however, it suddenly has become a matter of urgent public discourse. Consumer advocates have gone extensively on record as saying that tread separations would be rarer if cap plies were standard features on every tire.
"There's no question they would reduce the risk of tread separations," said C. Tab Turner, a Little Rock, Ark., attorney specializing in tire and SUV lawsuits and a legal counsel to auto safety Web site Safety-forum.com "They would make the tires more durable, more able to withstand highway conditions."
BFS, however, disagrees with Mr. Turner's assessment. "Nylon cap plies are used almost exclusively on high-speed-rated tires," the firm said in a prepared statement issued last Feb. 4, after KHOU-TV in Houston aired a report unfavorable to Firestone ATX, ATX II and Wilderness AT tires. "There is no scientific data or study that shows a durability advantage to tires with nylon cap plies at normal highway speeds."
The question of cap plies has become more public with the disputes arising in Venezuela over BFS' mislabeling of Wilderness tires for Ford Motor Co. as having the cap plies Ford requested. INDECU, the Venezuelan consumer protection agency, blames 62 accidents on the mislabeling and is threatening both BFS and Ford with fines and even criminal charges.
The issue remains a potent weapon for plaintiffs' attorneys in expert testimony in tire product liability cases.
In deciding to restore the $6.8 million verdict against Continental A.G. for Christine Morden, a driver rendered quadriplegic in a tread separation accident, the Wisconsin Supreme Court paid close attention to the testimony of Ms. Morden's tire expert, John Taylor, on the cap plies on Ms. Morden's Conti mud-and-snow tires.
Mr. Taylor told the original trial court that the cap plies on Ms. Morden's tires were "single-wrap," creating a single layer of nylon around the tires' steel belts, instead of "double-wrap."
"Double-wrap splices eliminate the weaknesses usually associated with a single splice," the court, quoting Mr. Taylor, wrote in its ruling.
The Wisconsin court also included in its ruling a description of a cap ply as "an additional adhesive to prevent belt separation. The cap ply wraps over the steel belts, runs around the circumference of the tire like an athletic bandage and holds the belts down together. The cap ply also prevents the tire from expanding in size as the tire makes its revolutions."
To Bruce Kaster, an Ocala, Fla., attorney representing various plaintiffs in cases involving BFS, Cooper Tire & Rubber Co. and other tire makers, the need for cap plies is scarcely worth debating.
"It's not my contention, it's a fact" that the plies are necessary, Mr. Kaster said. "It's well-established within the industry—by the field results from Pirelli when they introduced cap plies, by the actions of Firestone and other manufacturers who use them on high-speed tires."
Pirelli S.p.A. developed cap plies in the 1960s, and Uniroyal Inc. took out several patents on cap ply technology in the 1970s, according to Mr. Kaster. The actions of tire makers, he claimed, show their disingenuousness when they say normal tires don't need the plies.
"The Bridgestone Dueler, which is being used by Bridgestone/Firestone to replace the recalled tires, has a cap ply," he said. Pirelli places a cap ply on its SUV tire, the Scorpion, and on "98 percent of its other tires," he added.
Harold Herzlich, president of Herzlich Consulting, a Las Vegas-based firm which offers expert testimony to tire makers in liability cases, is far more skeptical about cap plies as a panacea.
"Cap plies have become a plaintiff's swan song," Mr. Herzlich said. "They use that argument about every tire being in danger of tread separation without cap plies as their argument of last resort."
The basic use of cap plies, Mr. Herzlich said, is to stabilize the tread area on high-speed and performance tires. To put this feature on every tire, he contended, might actually hinder safety.
"It creates an additional complication," he explained. "Any time you put another layer in, you create another potential site for failure.... I've seen tires with cap plies that fail from tread separation. A cap ply does not help if the tires are run underinflated."