Date: Sat, 16 Sep 2000 14:50:36 -0700
Reply-To: Steve Schwenk <steve@SYNCRO.ORG>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steve Schwenk <steve@SYNCRO.ORG>
Subject: SUV Roll Overs = Death Patch
Content-Type: text/plain; charset=iso-8859-1
Some good info is coming out of the Firestone recall
mess that has killed 88 in the us already. This info
is pertinent because the vanagon is vulnerable to roll
over due to its high center of gravity, the syncro more
so...and syncros with taller springs/ride height, even
more so. Roll overs more frequently involve fatalities
than most accidents. Some of you may recall last year
when a guy in a bus lost his entire family, although i
don't recall whether that was a roll over or
fire...caused by another driver, drunk i believe.
Tires are a critical factor, as is tire pressure, in
protecting yourself and family from roll overs. They
typically happen due to blow outs or sudden, corrective
action at higher speeds.
Here's parts of a piece in the NYT about the Explorer.
Sorry about the downer nature of this:
__________________________________________________________
But what has also emerged from Congressional testimony
and recently released internal company documents is a
picture of a tire, made according to Ford's design and
marketing demands, that has often been run to its very
limits. Indeed, in choosing those tires, Ford permitted
a narrower margin of safety than in many other
vehicles.
Not only does the combination of vehicle and
tire push the limits on weight and speed. The Explorer
itself, like many other sport utility vehicles with
high centers of gravity, is prone to roll over despite
what company documents show was an extensive but not
entirely successful effort by Ford in 1989 to make the
vehicle more stable. Taken together with the tire
manufacturing problems and a variety of human factors —
in essence, people tend to drive too fast and pay too
little attention to the age or air pressure of their
tires — the Explorer and the Firestone tires have
proved a deadly pairing.
The demands that Ford placed on the tires
reflect the difficult trade- offs the company faced in
trying to turn the Explorer, essentially an off- road
truck, into a more fashionable, refined vehicle that
would feel like a car during high-speed driving. To
give the Explorer a more comfortable ride and make it
less likely to roll over in everyday driving, Ford
chose a fairly low inflation pressure of 26 pounds a
square inch. But at low pressures, tires cannot
support as much weight and are more susceptible to
coming apart at high speeds.
...
And even with the tire- related deaths, which have
mostly occurred in rollovers, occupants of Ford
Explorers still have lower overall death rates, and
fewer deaths in rollovers, than occupants of other
midsize sport utility vehicles.
It is possible, although hard to confirm,
that in choosing a low pressure, Ford might have
actually saved more lives than have been taken in
tire-related crashes. Low- pressure tires reduce the
risk of rollovers
during sharp maneuvers. Even with the tire-related
rollovers, the death
rate in rollovers for Explorers is 42 percent lower
than for its main rival, the Chevrolet Blazer, which
uses a much higher-pressure tire but is also marketed
to a younger audience that may take more risks while
driving.
Then there is the question of weight. The
Explorer's tires have less overall capacity to carry
weight, in addition to the vehicle's own weight, than
do the tires on most sport utilities. The Chevrolet
Blazer uses the same size tires as the Explorer, for
example, but because they are inflated to 35 pounds a
square inch, they can carry 1,100 pounds more than the
Explorer's tires. A Blazer typically weighs 100 to 200
pounds less than an Explorer, too.
A Firestone technical document, presented at
a conference in 1998, shows that when the vehicle is
carrying even a modest load, more of the weight is on
the left rear tire than on any other tire — about 60
pounds more than on the right rear tire and 300 pounds
more than the front tires.
Tom Baughman, Ford's engineering director for
light trucks, said in an interview that the left rear
tire was the most likely to fail, but added that weight
did not appear to be the main reason for this. Ford has
nonetheless decided in the last several weeks that the
recommended
pressure for tires on the company's completely
redesigned 2002 Ford
Explorer, scheduled to go on sale next January, will be
at least 30
pounds for the front tires and 32 to 35 pounds for the
rear tires, he said. A month ago, Ford officials had
said that the pressure would be 30
pounds in the front and in the rear for the new
Explorer.
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