Making the Ford Mustang Shelby GT350R’s Carbon-Fiber Footwear a Reality
Behind a set of spotless glass doors on a small Deakin University campus in the small Australian city of Waurn Ponds, an hour southwest of Melbourne, Carbon Revolution creates what might be the most significant piece of the 2016 Shelby GT350R. The 526-horsepower, 5.2-liter flat-crank V-8 has been a bigger news splash, but behind these doors lies the real story. Until now, only a handful of Ford personnel and OEM partners (and potential OEM partners) have been beyond them.
“You know, we’ve kept this all under wraps for 10 years,” Carbon Revolution executive director Brett Gass says. If he wanted to mask his excitement, he failed. “It’s time for people to know.”
Read the Motor Trend comparison HERE: 2015 Chevrolet Camaro Z/28 vs. 2016 Ford Shelby GT350R Mustang
Working with Ford Motor Company for more than three years, Carbon Revolution has produced the 18-pound, 19-by-11-inch front and 19-by-11.5-inch rear wheels that adorn the GT350R, and they’re hands-down the most advanced carbon-fiber wheels in the world. They’re also the first composite wheels ever worn by a high-volume, crash-tested, fully vetted production vehicle. (Low-volume, multimillion-dollar Koenigsegg cars and their handmade pre-preg carbon-fiber wheels don’t count.)
Instead of the greenery of the vast university grounds, Carbon Revolution’s massive gray headquarters sits next to a cleared lot, rows of employee parking spots, and beyond that, a larger student car park where tardy Ph.D. candidates slalom through a sea of Aussie-spec cars and rickety bikes. Look closely, though, and you’ll see that car enthusiasts are toiling here, too. Over there is a track-prepped Lotus Exige S with a gigantic carbon-fiber splitter and scorched R-compound tires. Beside it, an immaculate all-white Audi RS4 Avant (with a six-speed manual!).
Why carbon wheels in the first place? Weight. Depending on application, the Aussie-built wheels are usually 45 to 50 percent lighter than an aluminum equivalent. The brand’s aftermarket 19-inch tall by 12-inch wide CR-9 destined for a Porsche‘s rear axle, for example, tips the scales at 17 pounds (7.7 kg)—yes, 17 pounds—and is equivalent to the OEM wheel in stiffness and durability. Its design even takes into account Porsche’s inner flange stiffness levels, which is essential to controlling a tire’s contact patch. “OEMs do what they call target cascading,” Gass says. “It’s making sure the whole vehicle is working well, making sure they’ve got the stiffness of the wheel matched to the suspension and tires.”
But contrary to popular belief, installing a lighter wheel does not automatically equate to better handling. “I actually looked at studies—I ran one myself on a Porsche,” Gass says. “I put a lightweight aftermarket aluminum wheel on the back of it, and I lost a tenth of a g on the skidpad because it wasn’t controlling the tire. The rim really deforms under the high-g cornering forces. You induce a lot of camber change with load, and if you are getting out of the OEM’s camber compliance setup, well, that is causing the vehicle to jump around, and it is not going to track right. You’re lowering the performance of the vehicle, in essence.”
The significance of matching OEM stiffness standards was especially evident on Porsches. “Porsche, for example, has done a lot of work to balance the camber budget,” Gass says. “We are not going to mess with what they have done at Porsche, so we benchmarked their wheel. Our wheel has the same range of stiffness. We have not messed with all the dynamics; all the genius Porsche has engineered remains. We just put in a replacement part. But we made it lighter.”
Aside from the inherent performance benefits—quicker, more communicative turn-in; less strain on associated structural and suspension components; shorter braking distances; faster acceleration; a more involving driving experience—there is the fuel efficiency advantage, too. On the Shelby, each wheel’s rotational inertia is cut by a massive 40 percent compared to an aluminum equivalent. And another, more surprising benefit: a quieter interior. Unlike an aluminum structure, a composite one absorbs noise. Sound doesn’t resonate as easily through layers of fiber.
Few outfits have pushed the niche of mass-produced carbon-fiber wheels as far as this team of about 100 manufacturing, engineering, and design experts. And outside of them, none has successfully established itself as both an aftermarket wheel maker and a Tier 1 automotive OEM supplier.
In 2007, says Jake Dingle, Carbon Rev’s CEO, the team determined they could successfully craft carbon-fiber wheels for premium aftermarket and OEM automotive applications. We’re talking the most premium of premium—a set of their aftermarket footwear costs around $15,000 USD. After that, they envisioned the technology’s fuel-saving and performance advantages trickling down to run-of-the-mill sedans and compact cars, even semi-trucks, jumbo jets, and military machines. But before any technological percolation could occur, they needed a product and a sustainable high-volume production plan that maintained the quality of their aftermarket and OEM goods.
Having the right people in place was imperative. It was no coincidence that each member of the executive team brought decades of knowhow from the aerospace, automotive, and composite industries. They were aces of mechanical and software engineering, business management, supply chain logistics, and assembly. Each placed an emphasis on teamwork, accountability, and communication. Nearly all held a Ph.D. If the Aussies had a dream team in business, these guys would be it.
“It started a bit earlier than that,” engineering and design director Ashley Denmead says of the company’s official establishment. “It started while we were at university doing undergrad work in mechanical engineering and working on a Formula SAE program. We were designing and building a race car from scratch. We thought it was a pretty good idea to make the wheels out of carbon fiber. It was easy to recognize, even at that time, that the wheels were the most important area to save weight. This was 2004 to 2007.”
Denmead’s side project blossomed into an obsession worth more than class credit. As Gass, Dingle, and commercial director Nick Batchelor secured private, personal, and governmental grants, Denmead and his band of talented young engineers went into high gear in their garages and labs. The fledgling company operated inside a former university warehouse.
The engineers went on a spree, vetting the globe’s who’s who of resin and composite suppliers, and as it happened, Carbon Nexus, one of the world’s foremost carbon-fiber manufacturers, was also based at Deakin. So too was a top resin creator, Commonwealth Scientific and Industrial Research Organization. (The university is a material science mecca.) The triumvirate’s close proximity allowed for the quick refinement of Denmead’s proprietary formulas and architectures. However, their relationship has always been one of research and development, not of supply. CSIRO and Carbon Nexus are not yet set up for such demands, Denmead says.
Computational analyses and real-world testing ensued. For years, Denmead engineered and integrated unique combinations of resins with freshly cut carbon-fiber weaves. Each layer needed to meet immense internal quality thresholds and be successfully replicated on a future production line set up by manufacturing director Greg Lindsay. After years of tweaking, they had the beginnings of a viable, fully replicable all-carbon-fiber wheel.
“Between this and this,” Gass says as he points to a computer screen littered with images of prototypes and sketches, “there are probably 20 or 30 different construction techniques. Even these, although they look like hollow spokes, they are not. They are actually open in the back. So our initial prototypes were more of an open-formed section, but that doesn’t work as well as our current optimized design. We went through multiple iterations of both manufacturing technology and architectures before we arrived at the hollow foam core.”
Their engineering approach was similar to that of an aerospace contractor or premium automaker. In fact, a number of their staff previously worked on Boeing’s composite projects. “With us, we break down the wheel into an assembly, so it’s a whole different set of subsystems,” Denmead says. “We have our material system that incorporates all the materials that we use, so what we actually have is a validation plan for introducing new materials.”
Each layer of dry carbon fiber is cut and formed into a “preform” shape. The preforms remain dry, but a chemical is applied to their surfaces (like starching a shirt). They’re then pressed into solid 3-D shapes and inspected for quality. From there, they’re placed inside Carbon Rev’s bespoke tooling and are infused with resin to create a single piece. The layers’ orientation forms a predetermined thickness, spacing, and stiffness level. Specific fabrics are used on different areas of the wheel to strengthen the entire structure. How the more than 300 pieces of carbon weave (each with 24,000 filaments in every visible strand) interface with material, bolted joint, and coating systems—and in turn how the entire product interacts with a vehicle’s particular axis behaviors and gross kinematics—is computer modeled to an exhaustive degree. Gass, a former vehicle dynamics engineer, devised most of Carbon Revolution’s internal vehicle dynamics analyses.
“This is the lateral g that the car is pulling,” Gass says as he demonstrates a simple animation of a mock vehicle. “It’s a little video game this is one of our vehicle model’s components, so you can see the data. I model all the suspension kinematics and tire and rim characteristics and calculate the tire contact pressure distribution in real time. It is an important step in the design process to understand how the wheel, tire, and suspension work together, and by looking at the computer model data, we can optimize the wheel.”
That whole process starts again with each new material they work with. “If we have a new resin system, for example, and it’s something different to what we currently have in terms of performance, then we’ll have to go through a whole qualification process for the new material,” Denmead says. “That’s very much an aerospace type of approach. For example, they can only build Boeing 787 parts from a qualified aerospace-approved carbon-fiber material. We have our own internal qualification standards for all the materials we use so that we always know that we’re not introducing more unknowns into a new design.”
Designing and testing the wheel’s patented bolted joint system, a collection of metal components needed to install the wheel to the vehicle (i.e. hub, hub ring, and lug bolt holes), undergoes the same level of scrutiny. “We came up with our own series of tests to ensure it’s working properly,” Denmead says. “One of the tests is getting the vehicle hub and clamping it with the lug nuts to the wheel, and we run that through our internal load cycle process. Then we check the lug nuts’ residual torque after it’s been through that thermal cycling process. And that’s because composite materials can be subject to stress relaxation, so you put them under load, heat them up, and the molecules might start to move. If they move, the wheel can come loose. We solve those problems with the materials we use and the patented design of that joint system. But if we change something in that system, like hardware or the material that’s involved, we have to retest.”
It turns out that coatings applied to composites are vastly different than those used on aluminum. “If you were making an aluminum wheel, it’s all about corrosion protection,” Denmead says. “For us, it’s about protection against ultraviolet radiation and all those sorts of things. The testing we do on our coating system is the full spectrum of weathering testing. We have chambers that simulate five years in Florida, so they’ll have moisture, salt, and ultraviolet radiation. And it keeps going through a cycle every day. The paint also stops the discoloration that can happen over time.”
Whenever and wherever he could, Gass switched into test-driving mode. He got into the habit of shipping Denmead’s handmade prototypes—and later production-spec units—to wherever on the planet he was stationed. He installed them on whichever latest sports car he rented, borrowed, or purchased and drove on them until the car failed. “I have never failed a wheel on a car,” he says. “I have, though, ended the life of many fine sports cars: BMW M3: dampers blown, cracked sub-frame. Porsche Turbo: snapped control arms, busted radiators. McLaren MP4-12C: transmission blown.”
He’s tested on all sorts of roads (including the Nrburgring Nordschleife) and hunted for the nastiest of pavements, including thousands of miles on Historic Route 66. He’d intentionally grind wheels on curbs and sought out foul weather. He would send his findings to Denmead and then wait for the next batch of prototypes to arrive at his hotel. The process would repeat until everyone on the team was satisfied. The wheel had to meet and exceed the industry’s standards, too, specifically those of Germany’s TV and Detroit’s Independent Test Services. The Hummingbird’s wheels passed with flying colors.
“That is my E46 M3,” Gass says, again pointing to his computer’s screen. “I had so many people telling me they would shatter if I hit a curb or hit a pothole. So we went and dug a pothole.” Contrary to popular belief, composite wheels will not shatter on impact—that is, if they’re built to withstand such traumas. In other words, unlike the aerodynamic elements that are designed to break on collision on race cars, the wheels are analogous to a carbon-fiber monocoque that is crafted to remain as intact as possible during duress; the layers of healthy carbon fiber below the surface arrest any cracks in the composite wheel.
Gass was a driving force behind winning Ford’s confidence back in 2012. As a former Ford Australia engineer who had stints in Europe and America, he was responsible for chassis development on some of the brand’s best-selling sports cars and SUVs. “Jake and I would do road trips over the years around the world and would first introduce OEMs to the fact that carbon wheels are possible and exist,” Gass says. The relationship with Ford was a natural fit. “I moved to Europe because we thought we’d attack Europe first. We were very active in Europe. Ford was one of the later OEMs we contacted, but they wanted to innovate and take the Mustang to new levels of performance.”
They’ve also developed close relationships with groups such as ITS in Detroit. “They’re quite influential in the industry and credible, as well,” Dingle says. “The fact that we’ve been running a lot of our validation with those guys and that they have deep relationships with North American OEMs—and some European OEMs—I think that formed part of the means of communicating what we were doing. It’s one thing for us to tell a customer that this technology is real and that it will be validated. But for the party that actually validate their products to communicate that to them is a much different proposition.”
They connected with Ford’s global manager for wheels and tires, Dave Rohweder, who, after interrogating the Carbon Rev team and seeing firsthand what their aftermarket wheels could do, mentioned they should start a project. “He really laid into me,” Gass says of the Rohweder meeting. Rohweder directed them to Hermann Salenbauch, head of SVT at the time. “And then we ended up working on the Mustang. Most automotive programs are small incremental changes. Rarely do you see a platform that has gone from way down in the rankings to implementing this much change. It’s a very aggressive and very innovative platform.”
The strength of their relationship with Ford is a major reason why it worked. “For something like this to go into a production vehicle environment, it needed to be 120 percent,” Dingle says. “The fact that we worked in a collaborative technical way rather than a supply-a-customer traditional commodity-type supplier relationship that really is what we’re seeing play out. There really needs to be that acceptance, that it is something quite different. And to get the benefit of that and to optimize it—frankly, just to get it done—certainly in this very early stage, there needs to be that collaborative engineering approach. The customers that get that, they love it.”
The nature of Carbon Revolution’s technology required their involvement in the Hummingbird project from the get-go. They took what they learned from their years of developing the aftermarket CR-9, all the production lessons and engineering know-how, to the next level with Ford. Ford demanded more tests. It was all part of the step up to the big leagues. “The wheels on the R car have been fully integrated into the suspension and chassis,” Gass says. “Ford’s been able to do that with their platform. It’s the first car to have that type of technology fully engineered into it.”
The Hummingbird’s wheel was required to meet more than 40 design validation program targets right off the bat. These included dimensional tolerances, fatigue tests, structural tests, chemical resistance tests, fit-and-function tests, bolt torque retention checks, and on and on. “This is the difference between aftermarket parts and us,” Gass says.
Carbon Revolution’s uniqueness is furthered demonstrated by its ISO/TS 16949 and ISO 9000 production certifications. There are also plans to bring resin and raw carbon-fiber manufacturing in house once the empty lot next to HQ gets permitted. If all goes as forecasted and future automotive OEM relationships are as symbiotic as they are with Ford, production will reach 50,000 wheels per year by October 2016. It could ramp up to 200,000 annual units once its military, commercial cargo, and aviation sectors are in full swing. Gass anticipates increasing their involvement in global motorsport, which he says also serves as a key forum for product trial and development. (Carbon Rev has had success with Red Back Racing’s Nissan GT-R in the Australian Targa Championship and with Don Law Racing’s Jaguar F-Type R at the Pikes Peak International Hill Climb.)
The day when many if not all street-legal vehicles ride atop stylish composite wheels might not be as far away as you think. And when that day does arrive, the small team at Waurn Ponds will without a doubt be at the forefront of the field. In the near term, however, expect to see a gradual adoption of such fancy footwear by a number of notable sports cars, including quite possibly the upcoming Ford GT.
“We can’t say,” a smiling Dingle says of the 600-plus-horsepower supercar that will use a carbon-fiber monocoque and body to curb weight. The CEO and his team take confidentiality quite seriously. “I guess you could look at the logic of the situation, though.”