Automotive Lightweighting > Carbon Fiber Comes to Performance Wheels > Christopher A. Sawyer
10 — Automotive Lightweighting
Formula SAE. Ashley Denmead, Carbon Revolution's
Design Director, was a member of one such team, and
that participation led to the frst composite wheels
appearing in 2004 on a Formula SAE car. The design
and idea behind it went through many iterations
before Carbon Revolution contacted European OEMs
in 2009 to see if they had any interest in lightweight
wheel technology, and what they needed to see from
a validation standpoint for such a safety critical
part. Three years were spent collaborating with them
to discern the necessary requirements for a compo-
site wheel.
What caught the OEMs' attention was that the
Carbon Revolution wheel could provide a 40% to
50% weight savings versus a factory alloy wheel
design. "For Porsche, our OEM-validated wheel is 15
lb. and the factory wheel is 26 to 28 lb.," says Dingle.
"That's a big weight savings." It took a lot of testing
with the German testing agency TÜV, talking to the
OEMs about their requirements, and developing a
validation program that encapsulates both OEM and
aftermarket standards. From a structural standpoint,
the tests fall into two categories: (1) an impact test,
and (2) fatigue tests. One is a bi-axial fatigue test
done in Germany that Carbon Revolution now does
in Detroit with Independent Test Services. "We baked
all of this together to create our own test criteria that
encompasses all of the most stringent checks, and
added another 30% on top of that."
In the test, a robotic arm presses the tire against
a rotating drum, loading up the wheel in both the
vertical and axial directions. The forces are based
on laps of the Nurburgring, and take four days to
complete. It covers 7,500 kilometers (4,660 miles),
a duty cycle that, Denmead says, "is equivalent to
p The GT 350's brakes aren't carbon composite, but an
aluminum and cast iron hybrid that takes up the diference
in thermal expansion by letting the cast iron disc foat on
captured brass pins. The 394-mm (15.51-in.) front rotors
can reach temperatures over 1,652°F, but do not tax the
proprietary plasma spray arc ceramic coating on the inner
wheel barrel and spokes.