October 9, 2001
Additional Firestone Wilderness AT Tires Have a
the Top Ten List
Detroit, MI (SafetyAlerts) - The National Highway
Traffic Safety Administration (NHTSA) has published a recall affecting
certain Firestone Wilderness AT tires installed on sport utility vehicles
(SUVs). These tires are sizes P235/75R15 and P255/70R16 manufactured by
Firestone prior to May 1998 that were either supplied to Ford Motor Company
(Ford) as original equipment or were sold as replacement tires.
Firestone has told NHTSA that, rather than contesting the decision, it will
recall the tires. In addition, the company says its dealers will offer to
replace, at no cost to consumers, these sizes of Wilderness AT tires that
are installed on pickup trucks.
"The American public is well served by removing defective products from the
road without delay," said Dr. Jeffrey W. Runge, the NHTSA Administrator. "We
are pleased that Firestone has taken this approach in lieu of lengthy court
proceedings, moving us quickly to a safe solution."
Firestone produced an estimated 3.5 million of these Wilderness AT tires.
They were primarily used as original equipment on Ford Explorer and Mercury
Mountaineer SUVs, to a lesser extent as original equipment on Ford Ranger
compact pickup trucks, and as replacement tires on these vehicles and
In August 2000, Firestone determined that a safety-related defect existed in
all Firestone P235/75R15 ATX tires and in Wilderness AT tires of that size
manufactured at its Decatur, Illinois plant, and recalled those tires.
NHTSA's Office of Defects Investigation (ODI) has conducted an extensive
investigation to determine whether other Wilderness tires, beyond those
recalled by Firestone, contain a safety-related defect, and whether they
should be recalled.
NHTSA's initial decision applies only to P235/75R15 and P255/70R16
Wilderness AT tires of the design supplied to Ford as original equipment. It
does not apply to other tire sizes of Wilderness AT tires, such as those
supplied by Firestone to General Motors and Toyota as original equipment,
since those tires have different design features and have experienced
relatively few tread separations.
Most of the tires subject to today's NHTSA decision were manufactured at
Firestone's Wilson, North Carolina and Joliette, Quebec, Canada plants.
Fewer than 100,000 of these tires, in the P235/75R15 size, were produced at
the company's Oklahoma City plant. Tread separation failures on the
Wilderness AT tires covered by NHTSA's initial decision have led to numerous
claims and crashes, approximately 50 injuries, and 25 reported fatalities.
Although these figures are lower than those for the recalled ATX tires, this
is because the Wilderness AT tires have not been in service as long.
Plant-by-plant failure trends for these tires are very similar to those of
the recalled ATX tires over similar periods of service. Their failure rate
is also significantly higher than that of competitors' tires used on SUVs,
especially the Goodyear tires used as original equipment on the Ford
The tread separations at issue in this investigation reduce the ability of a
driver to control the vehicle, particularly where the failure occurs on a
rear tire and at high speeds, and can lead to a crash. The likelihood of
such a crash, and of injuries or fatalities, is far greater when the tread
separation occurs on an SUV than when it occurs on a pickup truck. Claims
and complaint data indicate that a tread separation on an Explorer is no
more likely to lead to a crash than on other SUVs.
Like other radial tires, the Wilderness AT tires have two steel belts. Tread
separations typically begin as belt-edge separation at the edge of the top
belt, the area of highest strain in a steel-belted radial tire. Once
belt-edge separations begin, they can grow and develop into cracks between
the belts. If they grow large enough, they can result in catastrophic tread
detachment, particularly at high speeds.
In these Wilderness AT tires, the design of the "shoulder pocket" can cause
higher stresses at the tire's belt edge. The tires often exhibit a series of
weak spots around their circumference, leading to the initiation and growth
of cracks earlier than in competitors' tires and in other Firestone tires
used on light trucks.
A critical design feature used by tire manufacturers to suppress the
initiation and growth of belt-edge cracks is the "belt wedge," a strip of
rubber located between the two belts near their edges on each side of the
tire. The belt wedge thickness in the ATX and these Wilderness AT tires
produced prior to May 1998 is typically less than those of competitors'
tires. These tires did not adequately resist the initiation and growth of
cracks between the steel belts.
During March and April 1998, Firestone phased in a thicker wedge gauge,
which then became comparable to competitors' tires, and revised its material
composition. These modifications would tend to inhibit the initiation and
spread of the belt-edge cracks that lead to tread separations. Moreover,
there have been very few tread separation failures of the tires with the
improved wedge, and NHTSA's inspection of used Firestone tires indicates
that these tires have less severe cracks and separations between the belts
than tires built before these changes.
For these reasons, NHTSA did not include the tires with the improved belt
wedge in its initial defect determination. However, because tread separation
failures rarely occur in these tires until at least three years of use,
NHTSA cannot determine whether their actual field performance is
significantly better than the older tires. NHTSA will continue to monitor
the field performance of these newer tires.
On May 22, 2001, Ford announced a program to replace all Wilderness AT tires
installed on its vehicles. NHTSA encourages owners of all Ford vehicles with
P235/75R15 and P255/70R16 Wilderness AT tires built after April 1998 to take
advantage of the Ford program.
The rate of tread separation failures of Wilderness AT tires on Ranger
pickup trucks is lower than their failure rate on Explorer SUVs. This is due
to a variety of reasons, including the fact that the Explorer generally
carries higher loads, and its tires had a significantly lower recommended
inflation pressure, particularly on the rear wheels. Moreover, the
likelihood of a crash due to a tread separation, and of deaths or injuries,
is substantially lower on a pickup than on an SUV. Therefore, NHTSA's
initial decision applies only to tires installed on SUVs. However, because
the risk of future separations on pickup truck tires remain a cause for
possible concern, NHTSA is pleased that Firestone will offer to replace
these tires on pickup trucks at no cost to owners.
Consumers with P235/75R15 and P255/70R16 Wilderness AT tires can determine
whether their tires are covered by this action by checking the DOT serial
number on the tires, which is located in the lower sidewall area directly
above the rim flange. The tires are covered if the last number is "4," "5,"
"6," or "7." If the last number is "8," only those tires having 018 through
188 as the last three digits are included. Firestone dealers and retailers
will also provide assistance in this regard.
Regarding Auto Recalls
Frequently SafetyAlerts will list
auto recalls before
your dealer will know about them. If you have a vehicle
affected by one of these posted recalls be sure and
write down the NHTSA
CAMPAIGN ID Number.
If your dealer doesn't know about the recall when you
check, ask them how they are notified of recalls and
when the next update is due.
Did you know?
During 2001 there were over
1575 products recalled in the United
States for safety reasons!
How many did you hear
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