A highlight of the 2023 Chevrolet Corvette Z06 is the availability of lightweight carbon fiber wheels from Carbon Revolution, as we’ve seen previously on cars like the Ford Mustang GT350 and GT500 and the Ferrari’s 8 highest performing models.
These wheels save 41 lbs. of weight from the car, which is a lot for any component. Because this weight is eliminated from the car’s unsprung mass and from its rotational inertia, the effect is transformative.
Corvette executive chief engineer Tadge Juechter reports that replacing the Corvette’s excellent forged aluminum wheels with the Carbon Revolution wheels slashes 1.5 seconds from its lap times when running a track with approximately 2-minute laps. That’s a 1.25 percent improvement in speed without changing any other part of the car, which, on the race track, is a valuable and almost flabbergasting gain.
This advantage is enough that the $12,000 price tag for the wheels in clear finish or $10,000 in “carbon flash” black paint seems reasonable. Especially when considering that the painted stripes on the Ford Shelby Mustang GT500 were a $10,000 charge over the cost of adhesive vinyl stripes, and there was overwhelming demand from those customers for the painted stripes.
But this cost is expected to fall over time, as the manufacturing processes become faster and more automated, reports Ashley Denmead, Carbon Revolution founder and chief technical officer. “The goal is for the price to come down,” he said in an interview at the press launch of the Corvette Z06.
This is a challenge, because while the wheel incorporates a single molded piece of carbon fiber, the complete finished wheel is made of hundreds of components. “It is really a 3D jigsaw puzzle of 200 elements that go into the wheel,” said Denmead.
The cutaway image of a wheel on its side reveals the white filler material in the spoke area that is bridged by a carbon fiber "ski jump." The white horizontal band across the image is the ceramic heat-rejection coating on the inside of the rim. And the dark black embedded in the gray chopped fiber area is part of a carbon fiber band that surrounds the aluminum hub for added strength and stability.
One surprising detail is the fact that the wheels’ aluminum hubs are two halves that are pressed into the molded carbon fiber. They are not affixed by any additional means, as the clamping forces when the wheel bolts to the car reinforce the assembly.
An aspect of the wheels that is unique to the Corvette is the application of a white ceramic coating to the inside of the wheel to reject heat from the monstrous Brembo brakes. It is applied by a plasma gun spraying a liquified ceramic/aluminum mixture. It solidifies in a coarse finish whose porosity improves the layer’s insulation properties, while its white color helps reflect radiated heat.
The Corvette wheels represent the culmination of years of work, said Denmead. “Five years it has taken us to get to this point,” he recalled. “It is great to get here.”
It is no surprise that there was abundant potential mass to reduce in the Z06’s gigantic 20-inch x 10-inch front and 21-inch x 13-inch rear wheels. Their size also created some opportunity for innovation, as Denmead proudly pointed out some technical features visible in a cutaway wheel that show the internal construction.
The Corvette’s wheels are called a “hollow spoke” design, but the spokes aren’t actually hollow. They are filled with lightweight foam and short, chopped fiber that is strategically used to fill the void. But within that, for the Corvette, there is a diagonal strand of reinforcing carbon fiber that Carbon Revolution engineers dubbed “the ski jump.”
The size of a single wheel for the Corvette Z06 is astounding.
“We found that added a lot because the spoke is so wide,” Denmead explained.
While the stupendous size of the Corvette’s wheels and the similarly stupendous demands on them placed by the high-performance car make super sports cars seem like an obvious application for Carbon Revolution’s carbon fiber wheels, electric cars will also benefit from the wheels’ light weight, according to Denmead.
“We’re working on products now that have nothing to do with lap times,” he said. “Carbon fiber is an efficiency technology,” he pointed out. “If you reduce losses, it makes sense that you increase driving range.”
Also, the heavy weight of EVs is pushing carmakers to trim mass anywhere they can. “Customers have weight classification issues,” Denmead said. The aim is to reduce the price of carbon wheels to make them ubiquitous for EVs that need longer driving range.
One step that will help with that, and will help reduce the chance of future supply interruptions, will be Carbon Revolution’s production expansion outside Australia. “Eventually we’ll be manufacturing closer than Australia,” he said.