Carbon Copies

Ford details the carbon-fiber wheels created for the Shelby GT350R

By Steve Turner
Photos courtesy of Ford Motor Company

We knew that Ford Performance was pulling out all the stops when it was announced that the 2015 Shelby GT350R would roll on carbon fiber wheels. Reducing weight was a priority on the GT350 program, and it was prioritized even higher on the R-model. While carbon fiber wheels are definitely lighter, they offer more for performance than just reduced weight.

“The GT350R wheels and tires were developed to be the most track-capable parts we’ve ever produced,” Adam Wirth, chassis supervisor, Ford Performance, said. “The carbon fiber wheels reduce vehicle weight by 60 pounds compared to aluminum, yet are stiffer for better steering response.”

Naturally there are several challenges to bringing this sort of racy technology to a production car, but the benefits were deemed worthy enough to pursue the creation of one of the most high-tech wheels ever offered on a production vehicle. Building it for production means these wheels must be durable for the street and the racetrack. As such, Ford partnered with carbon wheel specialists, Carbon Revolution, to create them.

Before each wheel is finished with its production process, the GT350R carbon fiber wheel undergoes 61 individual checks. Tracked by an RFID chip embedded in the wheel, the manufacturer logs 246,000 data points before the wheel is released. However, the production testing is one thing, Ford puts these wheels through some rigorous real world testing as well. Not only must they withstand UV rays and road salts, but they also have to overcome curbs.

“A common misconception of carbon fiber is that while it’s strong, it’s also a brittle material. Some formulations may have this characteristic, but carbon fiber’s durability is a feature of the type of resin and design intent of the part. The wheels of Shelby GT350R are designed to be stiff, light and resilient,” says Ford. “One of the most severe tests for wheels in the Ford development process involves striking a curb at speed—a test that, without proper design, can cause serious wheel and tire damage. Because of the light weight, advanced construction methods and resins in the wheels, along with the highly developed MagneRide dampers, the suspension was able to react so fast that the driver wasn’t sure the test had been carried out correctly and ran it twice to be sure. The suspension response was fast enough to greatly diminished the severity of the impact—that’s the power of minimizing unsprung weight.”

Of course, testing the wheels for impact durability is one thing, but heat is another enemy they must withstand, especially on the racetrack. There brake temperatures are said to exceed 900 degrees Celsius. Clearly some of that gets transferred to the wheels, so they must be built to shrug off those temps. A key part of ruggedizing the front wheels for racetrack temps is a ceramic coating process born on the Space Shuttle program.

“Created specifically for motorsport and aerospace applications where extreme temperature conditions are encountered, Carbon Revolution’s thermal barrier coating system uses a multistage, multimaterial coating formulation that provides an excellent thermal barrier,” says Ford. “Using a plasma arc gun to liquefy a ceramic material, the wheels are coated at critical points around the inner wheel ‘barrel’ and on the back of the spokes. The result is an incredibly thin, nearly diamond-hard coating that reliably shields the resin from heat—reducing maximum wheel temperatures and allowing continuous track use by even the most aggressive drivers.”

All this technology allows the wheels on the GT350R to weigh half that of the aluminum wheels on the standard GT350, 18 pounds versus 33 pounds. Moreover, they have 40 percent less rotational inertia, which helps with handling and braking. Plus, they are so light the suspension can react more quickly to the road surface, which mandated an R-specific calibration for the MagneRide system.

“We believe this is a game changer for the industry,” Adam added, “a great example of improved performance through innovation.”

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