Additional photos by Forgeline Motorsports
Having been to several Optima Ultimate Streetcar Challenge qualifying events as well as many autocross and open track events, I can tell you that a serious G-machine begins with a good set of tires. Without a meaty and sticky set of rubber, none of the high dollar suspension, brakes, and engines mean a thing. And not only do you need good traction in the rear, but boatloads of it in the front, too. The front tires are going to do a great portion of the work when you hit the track, as the weight transfers to the front and you attempt to turn in. This is no doubt why the new 2014 Camaro Z/28 sports R compounds that are over 300mm in width. Unfortunately many of our beloved muscle cars are extremely limited in the front wheelwells, especially '80s G-bodies like our 1983 Buick Regal T-type ("G Machine") project, and not much better in the rear (thanks GM!). To make matters worse, there weren't any 17- and 18-inch off-the-shelf wheels on the market that would accommodate the size rubber we'd need. So it was going to take some creative thinking, custom made wheels, and a big hammer to make our dreams come true. Enter Grip Equipped.
When we first met Anthony Stephenson and Ben Hermance at Grip Equipped, we knew they'd be the perfect partners for this project. Grip Equipped's line of custom forged wheels is aimed at discerning muscle car builders, with an eye towards other applications and future endeavors. Ben crafted each of the nine different designs, with exceptional detail throughout – not your typical flat, one-dimensional type stuff that we've come to expect from 3-piece wheels. In fact, the lineup was created to capture the styling capabilities more associated with cast wheels, but without the weight and lack of serviceability. And because of the many options from lip design, finishes, center cap, machining, and hardware—each design is very flexible in terms of application and can look substantially different. When I first mentioned the project to Anthony, he immediately steered me towards the Rebel with a Brushed finish, satin black inner hoop, and gloss black center that would effectively emulate the early T-type wheels. Not only did I love the concept, but it was also relieving to have some help navigating through a seemingly endless list of options and combinations. I guess having a designer on staff comes in handy. Grip's fearsome two-some is made of two car guys that have had their hands in some impressive pro touring projects over the years, so clearly they get it. And it doesn't hurt that they've partnered with Forgeline Motorsports to manufacture and service Grip's wheels.
Now that we had selected our wheels, it was up to Dave Rushen and the crew at the Burlington County Institute of Technology in Medford, NJ to take the measurements and start on the long process of prepping the body. Ultimately we chose to go with an 18x9.5-inch front wheel and 18x12-inches in the rear – rather enormous by G-body standards. This necessitated some clearance on the inside of the wheelwells (more on that in the next installment), and since we elected to stick with the factory frame it also meant some massaging of the body would be needed to bring the wheels outward. We'll be using a set of GNX fender flares from G Body Parts and possibly even re-working the metal on the quarter panels. Hopefully it will resemble a vintage wide-body racecar, rather than a boy-racer wannabe. Follow along for the beginning steps of this serious project, and stay tuned for more.
1 A & B. Humble beginnings. The crew at the Burlington County Institute of Technology has already begun some of the body work as you can see. Once the wheels and tires are fitted, they’ll be massaging the body to meet the tires flush instead of sticking out and looking goofy.
2 For our rubber we’ll be using Falken Azenis, 275/35Z18 front and 315/30R18 rear, which are arguably the best 200-treadwear tire on the market for autocross and road racing. Though it was tempting to go with an R-compound for maximum grip, I have dreams of running in the Optima Challenge. But first we’ll actually need to get the car running and driving, I’m told.
3 Summit Racing sent us Percy’s WheelRite Wheel and Tire Fitment Tools (PN PHP-01201, $74.06) to help determine how wide we could go with the wheels and also select the backspacing. Using this tool should be step one in the process (before picking up tires). We happened to have the Falken’s sitting around from a previous project and that was the size we wanted to be at, so it was worth a shot.
4 After bolting the WheelRite to the front and rear, and rigging up the tires, Dave Rushen and the crew at BCIT were able to determine that the max wheel size would be 18x9.5 in the front and 18x12-inches in the rear. Like most GMs, the bolt pattern was determined to be 5x4.75-inches. With the 275s, Dave said we’d need 3.5-inches of backspacing in the front, and the rears would need 4-inches to fit the 315s. For the pad height, we used specs from the brake kit we’d be installing (you didn’t think we’d use stock brakes did you?), but ideally you’d have these in hand already to verify clearance.
5 Here you can see how the tool takes into account the frame rail. Since this is a road race setup, notching the frame would be a very bad idea. We couldn’t afford any loss in rigidity. In fact, we may need to add some braces at some point.
6 Fitting such a large front wheel/tire combo necessitated cutting the inner wheelwell, relocating the brake lines, and fender flares. Thankfully G Body Parts was able to accommodate us with these fiberglass GNX fender flares. These pieces are made to order and cost $275 thanks to G Body’s brand-new molds. The fit and finish is pretty smooth with the black gelcoat finish, though it will obviously require sanding and painting – more on this next time.
7 With specs in hand, we called Grip Equipped for a custom set of 3-piece wheels. Forgeline Motorsports manufactures the wheels for Grip Equipped. This is the raw forging of 6061 T-6 aluminum that is to be the Rebel wheel’s center, which is forged on a 6,000-ton hydraulic press. At the very beginning of the process, designer Ben Hermance must decide if the wheel is to be a shallow, concave, or standard (convex) style. Then his design is put through Finite Element Analysis to ensure there are no weak points, and tested beyond SAE standards using a real-world load variable.
8 A & B. From there the raw forging is turned on a lathe until it takes this smooth appearance, and starts to take shape.
9 The CNC machine cuts the spokes out next. Just look at all the excess material left over! The weight savings in forged wheels is not only due to the material, but the machining as well. Best of all, there is no sacrifice to strength – these wheels should last the life of the car no matter how hard we run it.
10 After the centers leave the CNC machine, there is an extensive deburring process in which they are sanded by hand and prepped for finishing. All this TLC really makes the difference.
11 Last but not least the outside lip and inside shell are assembled once they have gone through the finishing process, and then the centers can be joined using ARP hardware. If the wheels ever become damaged, they can be taken apart and serviced in the same manner rather than having to scrap the whole thing like with a cast wheel.
12 A-D. Voila! Here is the finished product. Not only are these wheels amazing to look at in pictures, but the little details are incredible from the hardware to the powdercoat and valve stems. And we’ll never have to worry about whether our cast wheels might crack and come apart at the track. For more information and pictures of the wheels being built, go to http://bit.ly/17VaW3E.