uploaded 3/12/2008
Goodyear's Bad Decisions at Atlanta
The NASCAR drivers are right! Goodyear made a really dumb
decision when they brought only one tire to run on the Nationwide
and Sprint Cup cars at Atlanta.
These cars are now way too different to use the same tire.
The tire was fine for the older car design but unstable on the
new car. As a result the teams couldn't find a setup that gave
the driver a car that was balanced for an entire stint. It doesn't
help that these tires give-up two seconds a lap during the first
20 laps of a tire stint.
Some drivers were more vocal than others but I'm glad they
spoke up. The real problem here was not bad tires but a badly
managed program. Goodyear and NASCAR both need to be more respectful
of the drivers and teams. The tire is the most critical component
in the system by far and the loads applied during racing on high
banks at close to 200mph are huge.
I'm also glad to hear that Texas Motor Speedway has announced
the Atlanta tire will not be used at their track. If NASCAR and
Goodyear make poor decisions then other stake holders in the
racing industry need to step up and protect their interests.
Goodyear's press release touting, "...our engineering,
research and tire development is second to none." is ridiculous.
They make good tires but their R&D is second rate compared
to Bridgestone and Michelin.
Goodyear also says that Tony Stewart was wrong when he said.
"They exited out of Formula One. They exited out of IRL.
They exited out of World of Outlaws and there is a reason for
that. Goodyear can't build a tire that is worth a crap."
The Goodyear press release blames escalating costs as their reason
for ending competition in CART and F1 racing.
In my book, The Racing & High-Performance Tire, I explained
how Bridgestone reentered racing with the CART series in 1994
and quickly forced Goodyear to the back of the pack. Bridgestone
won races with tires that were almost as fast as Goodyear but
they gave up much less during a tire stint than Goodyear tires.
Here is an excerpt from the book that explains how two very
different tire tread compounds respond to the abuses of a race
car.
Tire Give-Up
Rubber abrasion is mainly caused by two mechanisms working
simultaneously: 1) abrasion due to rubber fracture and 2) mechanical/chemical
degradation of the rubber surface. The fracturing mechanism is
actually two processes. A loss of "fine-scale" rubber
in very small particles removed from the areas between the peaks
in the patterns and "larger-scale" particles abraded
from the upper sides of the ridges.
The mechanical/chemical degradation is what's interesting.
This type of abrasion is caused by large frictional forces on
the surface of the rubber. These forces cause rapid elongation
of the polymer chains resulting in rupture of some individual
chains. When a chain breaks the broken ends produced are chemically
active and will reattach somewhere if they get the chance.
What happens next depends on the chemical nature of the compound.
Broken chains in natural rubbers and styrene-butadiene rubbers
look for a free radical and usually find oxygen, since wear is
a tread surface process. A combination with oxygen stabilizes
the ends of the broken chains, resulting in a tendency toward
shorter chains and a lower molecular weight in the compound,
producing a sticky, oily residue. That's what a hot Goodyear
tire looked like during the CART tire war.
Other rubbers, polybutadiene for example, join with other
chains after breakage, resulting in additional crosslinks. A
higher percentage of crosslinks is a tendency toward a higher
molecular weight, producing an abraded material that is dry and
powdery. That's how the hot Firestone tires looked.
What myself and other people saw during the CART Firestone/Goodyear
tire war were tires that looked very different when they were
hot. The Goodyears got black and wet looking. They seemed oily
and abraded rubber rolled off in greasy hunks. The Firestone
tires looked dry and gray. Their debris was dry and powdery.
Years ago I had a conversation with a Firestone engineer who
shall remain nameless and the subject of that talk fits into
this discussion. I was doing my usual deal of asking different
people the same question and comparing the answers to try to
piece together some relevant information. The subject was what's
going on with tire give-up and I said something like this. "I
guess a tire working hard on a racecar is getting some intense
heating and mechanical working. I'd think this would break some
of the polymer chains and crosslinks. Is that what causes give
up?"
This engineer said something like, "Yes, I think so,
but there are things you can put in the compound that encourage
the broken chains to reattach and that retards the degradation
of the compound." That fits with the process I described
above.
The question remains why Goodyear continued to make tires
that got hot and greasy instead of gray and dry. Of course I
could be wrong about this oily/dry difference, but even so the
question remains. Why didn't Goodyear respond?
Either it didn't know how, or it didn't have the money to
develop the technology. Goodyear was trying as hard as it could
with the materials and processes available. Firestone had its
own materials and processes which Goodyear was unable to duplicate.
It was obvious at the time that Goodyear had no recourse and
had to quit rather than be repeatedly beaten on the track.
There's a lot of misinformation about tires. People say "Hard
running forces the oils out of the rubber." I think this
oily residue is what they're talking about but I don't think
it actually has anything to do with the oils used as extenders
in rubber compounds.
That's the end of the excerpt.
Back then if Goodyear had been able to produce a winning tire
they would have! Bridgestone entered competition in Formula 1
also and Goodyear had to quit or be soundly beaten.
Leo Mehl, Goodyear's Worldwide Director of Racing, retired
during this time. He never spoke on the record about why he quit
but those of us who talked to him figure he wouldn't have left
Goodyear if he had been given the financial and technical support
necessary to compete.
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