Take A Closer Look At Finspeed's Wheel Manufacturing System
Take A Closer Look At Finspeed's Wheel Manufacturing System
A forged, one-piece aluminum wheel is the lightest, strongest construction aluminum wheel available to performance automotive enthusiasts. However, that conventional wisdom doesn’t guarantee that all aftermarket one-piece forged wheels are machined and finished with the same quality standards—even if the initial forged blanks come from the same source.
Finspeed produces wheels from traditional one-piece forgings, yet there are distinctive variations in the design and manufacturing process at the work that set a higher benchmark within the performance community.
“Everything we make is application specific,” says Finspeed founder Daniel Finke.
Those shopping for performance one-piece wheels will note that there are three other popular wheel aluminum wheel manufacturing methods that don’t offer the strength and durability of a one-piece forging:
• Cast wheels - Molten aluminum is poured or pressure-fed into a mold. It’s an inexpensive process but the wheels are much heavier due to the extra material required to compensate for the porosity (micro bubbles) when the molten metal cools.
• Flow formed or rim rolling - Starts with a simple casting, then that casting his reheated. The outside barrel portion is spun and stretched over a drum to the desired shape.
• Billet - A huge chunk of billet aluminum is machined into the final wheel size and shape. Even a machined billet wheel isn’t as strong as a forged wheel, and it can be three to four times more expensive due to the amount of machining required.
Forged wheels start out as a small block of billet aluminum that is pressed between forging dies under intense heat and pressure into the basic shape of the wheel. The forging process produces a very dense and strong molecular composition. Traditional forging aligns the grain structure in the direction that the material flows. Ideally, that aligned grain structure is perpendicular to how the stress will be applied—which further enhances the metal’s strength.
The rough forging is then machined and finished into the final wheel dimensions and style. It’s these final production steps where Finspeed takes a more meticulous approach and differentiates itself from the competition.
Virtually all aftermarket wheel manufacturers (cast, flow-formed and forged) start with a typical wheel size—for example, 19x11 is popular for many fitments. They will overlay different brake profile drawings to check clearance and ultimately settle on a wheel profile that is suitable for many different applications. This wheel profile is pre-produced with a trendy spoke pattern. As the company receives a customer’s orders, those pre-manufactured wheels have the hub bore, lug pattern and offset machined to fit the final application before final finishing is applied.
“At Finspeed, our philosophy puts the priority on producing the best possible product, rather than an adequate product that is easy to make,” says Finke. “This, of course, is significantly more difficult to do as compared to how the forged wheel industry does it, but it produces a superior product.”
Again using a 19x11 wheel as an example, this size is common on the front of a C7 Corvette, Nissan GTR and Dodge Viper in addition to the rear on the C5 and C8 Corvette, Ferrari 488, Lamborghini Huracan and several others.
“If you are building for performance, even with the same wheel model from the same manufacturer, none of those wheels should be the same,” explains Finke. “Yet, that is how virtually all of the forged wheel industry does it. The only changes are the final finish and to allow the wheels to be attached to the vehicle while fitting under the fenders.”
Continuing with this scenario, Finspeed offers a specific profile and spoke shape for each 19x11 wheel used in the aforementioned applications. These individual designs are guided by internal performance benchmarks and the type of customer driving. Redundant versions will be sold only when the same model and size is ordered for the same application.
Finspeed’s manufacturing process is also different from the typical industry methods. The company—which had no conventional equipment or standard wheel production experience in the beginning—had to design and build its own work-holding fixtures along with other tools necessary to produce a quality product.
“We started with a philosophy and a target product, then had to figure out how to make that product efficiently. If you want something better than what is available, you cannot get there doing things the same way,” says Finke.
No wheel company has its own forging presses; they’re just too expensive and complex. Like most of the premium wheel companies, Finspeed gets its forgings from a California-based aluminum products supplier. Again, working with the 19x11 example, instead of trying to cover all applications with a single off-the-shelf forging from that supplier, Finspeed has access to many 19x11 forging profiles - including those that are proprietary to Finspeed - to provide the proper wheel for the specific application.
Also separating Finspeed from many other wheel companies is the machining process. With most of their turning work, there are two tools running simultaneously in each lathe to speed up production.
“We use bigger, more powerful machines. This allows me to buy larger forgings that enables more profiles and applications, and it's not going to take me 45 minutes to remove that material,” explains Finke. “It only takes me five to 10 minutes with the machines that we use. I’m willing to pay a little more for material up front to have fewer limitations and more flexibility in machining the profiles of the spokes, barrel and so forth.”
Once the wheel profile is turned and bead knurling is applied, the wheel goes to the mill where the spokes and accompanying features are machined.
“We use five-axis mills to machine our spokes. Having five-axis capability is the only way I can implement some of the features and shapes required to meet our performance benchmarks,” says Finke. “We incorporate complex undercuts, angles and profiles that would be impossible to produce in a timely fashion without it.”
Finspeed works closely with customers to build wheels that meet their performance and aesthetic demands. If a customer sees a Finspeed wheel package on a winning vehicle, the wheel model can likely be developed to fit the customer's needs, regardless of the application. Often customers are unsure of what they need, yet they know their objectives. As a result, it's not uncommon to have an intense consultation and even a little schooling in wheel dynamics.
“Generally, the fewer number of spokes, the heavier overall the wheel will be. This is not something that is widely understood. If a racer insists on our F5, five-spoke wheel (many drag-racers do), we’ll certainly make it robust enough to accomplish the task. But, we’ll also let them know that the wheel may be heavier than the same fitment on a different wheel model with more spokes,” notes Finke.
Finspeed has a bespoke program as well; often producing wheels that work with modern, readily available tires, but are similar to and appropriate for vintage applications long out of production. This service is becoming popular with the Pebble Beach crowd.
When developing wheels, Finspeed engineers utilize ANSYS FEA (finite element analysis) computer modeling software to understand and test the dynamics and loads that will exceed what the wheels will be subjected to while in competition.
“There’s a reason Formula 1 teams use ANSYS—it’s highly configurable, accurate and consistent,” says Finke. “It’s expensive, but it’s what we require to do the job. I certainly would rather spend less on our simulation software, and we evaluated several different, less-expensive, packages. ANSYS was the only package that performed.
Finspeed simulations are constantly validated and improved with physical testing to confirm the engineer’s projections. The company often sends wheels for physical testing to determine failure loads and locations.
"We don't use physical testing just for certifications, but to learn and get better. We've routinely tested up to failure. I will challenge our engineering staff to predict when it will happen and at what load, which is well past SAE certification levels,” explains Finke. “We then go back and adjust the factors in our load calculations and simulations based on what we're seeing. We get smarter and better at what we do; always looking to be more accurate, down to the tenth of a percent.”
Finspeed engineers regularly hear from new and potential customers who send them photos of a competitor’s wheel that failed in competition or under some other performance stress situation. Finke says most failures are located where the spoke meets the hub or the spoke meets the barrel of the wheel.
Racers are sometimes tempted to consider wheel aesthetics over performance; however, Finke says the two qualities are often compatible.
“I have always found that if you fully optimize the wheel, it ends up looking really great,” he says. “Again, our philosophy is application-specific. If I have a customer with an exotic who participates in mostly cars and coffee events and wants different colors for the barrel and center, a modular wheel is more appropriate. We can do those, too.”
“I shape my recommendation based on what the customer's trying to accomplish,” sums up Finke. “That's always the first question. What do you want to do with the car? What tire are you going to be running? We always start there.”