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Bridgestone/Firestone links
tire failures to design, plant
12/19/2000
Associated Press
WASHINGTON – Bridgestone/Firestone Inc. has told government
officials investigating 148 U.S. traffic deaths linked to its tires
that the problem stems from a faulty design and unique manufacturing
process at its Decatur, Ill., plant, The Associated Press has
learned.
The Nashville, Tenn.-based company said it would release its
findings about why some tires came apart today and would not comment
beforehand.
Two sources speaking on condition of anonymity said
Bridgestone/Firestone officials told congressional investigators and
the National Highway Traffic Safety Administration that the Decatur
plant uses a different process to mix rubber that has resulted in
the tread peeling off the tire, causing the accidents.
One of the sources works on Capitol Hill; the other is an
official familiar with the report. Both spoke late Monday.
The tire maker also told investigators there was a problem with
the wedge area of the tire, located near the shoulder where the
tread meets the tire wall. And it continued to blame Ford Motor Co.
for recommending a lower inflation pressure.
The company's recall, which began in August, is one of the
largest in U.S. history. The tire problems have been subject to
high-profile congressional hearings and investigation and prompted
Congress to pass an overhaul of U.S. tire safety regulations.
As reports of traffic deaths mounted over the summer, the company
was unable to explain why so many tires came apart on the road.
The report backs up the company's contention that the problem is
concentrated in Decatur.
The current recall is concentrated on – though not limited to –
tires made in Decatur.
In its report, Firestone blames the failures on a complex
combination of factors, including temperature and type of climate
they're used in, loading of the vehicles, speed, place of
manufacture, shoulder design and tread design.
And Firestone still insists that the lower inflation pressure
recommended by Ford Motor Co. played a role in the tire failures.
Bridgestone/Firestone also says that the Explorer's weight
increased beginning in 1992, requiring a higher inflation pressure
that left a small margin of safety for the tires, the congressional
source said.
Ford recommended that Firestone tires on the Explorer sport
utility vehicle be inflated to 26 pounds per square inch, while
Firestone recommended 30 psi.
A Ford spokesman, Ken Zino, said the auto maker is continuing its
investigation and has yet to come up with a root cause for the
failures. He said the Explorer's weight has not changed
significantly.
"In our discussions with both NTHSA and Firestone we discussed
tire design and manufacturing problems, and we still don't see the
Explorer as the issue," Zino said.
NHTSA links 148 deaths and more than 525 injuries in the United
States to separations, blowouts and other tread problems in
Firestone's ATX, ATX II and Wilderness AT tires, 6.5 million of
which were recalled during the summer, many made at the Decatur
plant. Many of the tires were standard equipment on the Ford
Explorer.
Ford and Firestone officials briefed NHTSA on the status of the
investigation last week. Firestone officials met Monday with
congressional investigators, while Ford officials plan to meet with
them Thursday.
The Decatur plant uses a process known as pelletizing, where
rubber pellets are blended with a lubricant to create the rubber
that coats the steel belts of the tire.
This process is unique to Decatur. Other plants use a slab system
that does not involve pellets.
The lubricant apparently causes a breakdown in the tire that can
cause separation of the tread, the sources said.
But the vice president of the United Steelworkers local 713 at
the Decatur plant said it isn't fair to drop the whole problem on
the doorstep of one factory.
"I feel like they're questioning our workmanship," Harland Smith
said. "We have tires out there with 80,000 miles on them. ... We
have workers at our plant that drive on them same tires and never
took them in for the recall."
Smith believes the tire failures more likely came from overall
design problems and more significantly from the lower inflation
pressure recommended by Ford.
"Underinflating the tires puts more heat and stress on them,"
Smith said. "Most of the failures happened in hot states down
south."
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