Forgeline Wheels Reduce Rotational Mass On Project M-Track3r

For automotive enthusiasts, choosing a wheel is one of the hardest decisions to make. For Project M-Track3r, we needed two sets for some extensive tire testing that we’ll be performing with the car. The dual sets will allow us to have two compounds mounted and ready to test when we get to the track. We knew that the wheels had to be light, strong, and stylish so we hit up our friends at Forgeline for a set of RS3s from their new Heritage Series, as well as a set of their aggressive, lightweight GA3Rs.

 We couldn’t just put any wheels on our E46 M3, though.

When searching for the perfect track wheel, it all comes down to material, style, sizing, and finish. Track day enthusiasts naturally prefer a smaller diameter, lighter wheel to reduce rotational mass and unsprung weight, but style is still a big factor. The car has to look good while it’s out on the track, right? Take a stroll with us as we take a look at the wheels, the production process, and finally install them on Project M-Track3r with some fresh, meaty tires. We also talked to Forgeline’s David Schardt about the wheels’ manufacturing process and some stand-out features.

The Wheels

For more than 20 years, Forgeline has applied their passion for motorsports and racing to design and produce high quality wheels for street and track use. Their wheels can be found on some of the fastest racecars to be campaigned in United SportsCar, Grand Am, American Le Mans, and many other amateur racing series in the Continental United States. We like the fact that there is a lot of racing influence that goes into these wheels. It assures us that the wheels are capable of withstanding the kind of abuse we’re going to put them through.

The first set of wheels for Project M-Track3r are the new RS3s from the Heritage Series. This wheel is the modern, modular version of the RS Competition wheel that was really popular in the 90’s and still is to this day. With its classic design, the RS3 features a simple and sophisticated, yet muscular five-spoke style with tapered spokes and smooth edges.

The wheel centers are machined from 6061-T6 aluminum and are secured to the heat-treated rim shells and polished stepped lips via ARP titanium fasteners. The titanium fasteners don’t come standard on these wheels, but can easily be opted for.

After some research on wheel sizing for our M3, we concluded that 18 x 9.5 was the perfect fit in all four corners with an offset of +30mm up front and +18mm out back. As far as finish options go, we chose the titanium for the center and brushed nickel for the lips to give the wheel a subtle, aggressive look. “The titanium hardware is simply for weight savings. That weight is in the most critical area of the wheel because the farther out the weight is in the wheel, the more momentum its driving. If you can take a pound out of the wheel in that most outer diameter, it’s actually more than if it was a pound taken from the center of the wheel,” explained Schardt.

Our second set of Forgelines are the GA3Rs. The GA3R was designed purely with racing in mind and it shows because the wheel is actually permitted for use in racing applications. Engineered with a 2,100-pound street tire load rating, the GA3R ensures strength and structural integrity on and off the track. Being the lightest wheel that Forgeline offers, titanium hardware comes standard on the GA3R. To seal the wheels, Forgeline uses a fast-drying, high-strength sealer, sourced from Loc-tite, that is resistant to leaks and is quick and easy to repair.

For this set, we decided to go with the Satin Black on the face of the wheel and a unique Transparent Smoke color, similar to black chrome, for the lip of the wheel.

Another cool feature of the GA3R is the “I-beamed” spoke technology, which reduces weight and applies additional rigidity within the spokes of the wheel. “The spokes have I-beams cut into the sides of them which makes them lighter, but doesn’t affect their strength at all. Anything that requires a lot of strength in any kind of construction, I-beams are used, so we’re just using that technology to strengthen the wheel,” Schardt stated.

Monoblock Wheels

For those that didn’t know, Forgeline also produces a line of strong, lightweight forged monoblock wheels that cater to the average street-going vehicle, as well vehicles that often see the racetrack. Each wheel is machined entirely out of a 6061-T6 aluminum forging. The result is a surprisingly light, strong wheel that deflects less under rigorous driving conditions. Brake caliper clearance is generous with the line of monoblock wheels and, just like any other wheel from Forgeline, these can be made to custom specs, complete with finish options.

To test the wheels for strength, Forgeline uses a method called FEA (Finite Element Analysis), and it is a numerical procedure for analyzing structures. FEA is huge in the wheel industry because it allows designers to see all of the theoretical weaknesses within the structure.

In case of structural failure, FEA can be used to determine the modifications needed to meet the new condition of the design. “We’ve done so much testing in the past and now we’re doing FEA, but we’ve been able to validate with physical tests that our FEA is very, very accurate at this point. We’re just making sure that every wheel can withstand the forces of a racetrack, or a heavy car, or anything along those lines,” Schardt explained.

The production process of Forgeline’s wheels is pretty cool, too. The wheel starts out as a drawing in CAD software where it is then tested for points of weakness and stress – this is where FEA takes place. Once a design is chosen, Forgeline begins the machining process with a blank 6061-T6 aluminum forging. On a lathe, the back of the wheel center is cut. Once that part is complete, the wheel center is transferred over to a 4-axis CNC mill where the design is machined into the center.

The left photo shows the wheel centers after they come off of the lathe. The right photo shows the wheel center's design being machined.

First, the CNC mill cuts the spokes and overall design out. From there, the bolt holes are cut, followed by the assembly bolt holes. Lastly, the CNC machine mills the pad to the proper offset of the wheel being built. After the faces of the wheel are milled, they are sent over to the polishing room for a rigorous inspection of any machining lines that are still visible. Those are eased out by hand. If the wheel centers are to be polished, they stay in the room, but if they’re getting powdercoated, they will be sent to the appropriate area after inspection.

After powdercoating comes the final assembly of the wheels, which is where all three pieces of the wheel come together. The parts of the wheel are secured together via 40 ARP fasteners and each one is torqued to 25 ft-lb. The next step after assembling the wheel is to seal it. This ensures that there are no leaks once the pieces of the wheel are secured together. When the wheels are finished with final assembly, they’re sent to the final inspection room where the wheels are checked by hand for any flaws and cleaned.

Left: The wheel being sealed where the face, lip, and barrel meet to ensure that there are no leaks. Right: The wheel being properly tested for runout.

Of course, all wheels have to be round. Part of the inspection process includes checking the wheels for runout, which is done by putting the wheel on a turntable-type stand where the wheel can spin freely. A dial caliper presses up against various parts of the outer wheel to check for excessive runout. Generally, the wheel industry has a runout tolerance of .030 of an inch, but Forgeline goes the extra mile and uses a tolerance of .020 of an inch for all of their three-piece wheels.

Once the wheels are cleaned and pass inspection, they are ready to be boxed up and sent to the customer. Forgeline does have tire packages available upon purchase of the wheels, but we didn’t opt for that because we’re going to be swapping tires often during our tests.

New Shoes For M-Track3r

As we stated earlier, we are going to be testing various tires on these wheels throughout the car’s build and we will be using our spiffy new Racelogic PerformanceBox to gather data. The first tire we’ll be testing on the RS3s is Falken‘s Azenis RT-615K. We had the tires mounted and balanced in-house by our shop manager, Sean Goude, who did a great job. It’s very important to have the tires mounted by a trained professional, as the sealant and the wheel itself can be damaged during tire mounting.

Left: Before we mounted the GA3Rs, we put one wheel on the scale and it weighed out to 20 pounds and 10 ounces. The RS3s have significantly more material on the faces, which cause them to be 3.5 pounds heavier per wheel than the GA3R. Middle and left: The Toyo Proxes RRs being mounted on the GA3Rs

Being that the GA3Rs are the lighter wheels out of the two sets, we mounted our second set of tires, DOT-approved Toyo Proxes RRs, on them. After mounting and balancing the wheels and tires, we got them on the car to see how they look and fit. Instantly, we knew that our Forgeline wheels were a perfect fit for the attidude of the car and the direction the build is going.

We’re excited to put these tires to the test using our sets of Forgeline wheels. With Forgeline’s wheels heavily influenced by motorsports, the quality and attention to detail is amongst the highest in the wheel industry. Putting around town or out tearing up the racetrack, Project M-Track3r will always look nice and perform significantly better than when we had the heavy 19-inch cast aluminum rollers on there previously. We will also be testing various other components with Project M-Track3r in the near future, so stay tuned!

 

 

 

 

About the author

Josh Kirsh

Born in Van Nuys, Raised in Murrieta, Joshua Kirsh is a SoCal Native. With a love for anything on wheels since the ripe young age of two, Joshua Managed to turn his love for automobiles into a career. As Power Automedia's newest writer, he plans to bring you some of the industry's hottest news topics while he's not out in the shop wrenching on some of our badass in-house project builds.
Read My Articles

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