Hey all you Poncho fans, check out our latest update of Street Muscle’s Pro Touring 1968 Pontiac GTO affectionately christened, Project Payback. We saved this forlorn example of John Delorean’s trail-blazing muscle car from the jaws of the crusher and granted it a new lease on life. It is a bit crusty around the edges, but it will emerge from its hibernation as a feisty track demon with the best of the best, go-fast components.
Getting the wheels and tires “right” on a build is one of the most critical stages of a project, and we’re gonna break that down for you, here. Not only do we want the car to “sit” right with the perfect stance, but in the case of Project Payback, we want the functionality to be there as well. In other words, we want to attain the perfect mixture of performance, handling, and looks. No janky ride or rubbing wheelwells either.
With a stout new frame and suspension from Schwartz Performance, we needed a set of wheels and tires to fit our unique application. We want rolling stock that looks amazing and is lightweight and strong. Strong enough to not only drive on the street and autocross, but also take to the road course without worrying the wheels would crack or break altogether.
We went with Forgeline wheels because they make an incredible product that checks all the aforementioned boxes. Although we chose the 18″ DS3 model with a “Dark Transparent Smoke” center, “Transparent Smoke” outer rim, and “Matte Graphite” inner rim shell, the design variations are truly endless.
Forgeline elaborates, “Every forged wheel is custom made-to-order for each individual customer and each unique vehicle application. This extremely resource-intensive manufacturing process ensures that every order is individually engineered, precision machined, hand-finished, and custom powder coated to deliver a perfect vehicle fitment and to fulfill each customer’s personal creative vision.”
Forgeline is the 800-pound gorilla in the room when it comes to custom wheels, and for good reason. The company was formed in 1994, with the express purpose of building custom lightweight forged wheels for road racing applications. For more 27 years, they’ve applied their racing experience toward designing and building wheels that can withstand the extreme demands of sports car racing, as well as the street. With a commitment to strength, safety, and performance, they have earned their place on some of the world’s finest race cars and track bandits.
Meanwhile, back at Project Payback’s lair, we needed a skosh more room in the rear wheelwells so we tubbed them with sheet metal from ABC Performance, based out of Imlay City, Michigan. They are stamped steel, just like an OEM panel, and are expertly fabricated. To perform the metalwork, we called Best of Show Coachworks in Escondido, California. We had a head start with this mod because the frame rails on Project Payback’s Schwartz chassis are made to accommodate wider rear wheels and tires. With a stock chassis, you’d also need ABC’s full kit to cut and plate the frame rails. Another bonus with the tubbed rear fender wells, is we gain enough room to avoid rolling the rear fenders.
To calculate our backspacing, we relied on a primitive but effective tool we bought years ago. It’s called Percy’s Wheel Rite, and we purchased it from Summit Racing. It’s an old-school solution but it works for us. You basically have to screw and unscrew the arms to calculate the diameter, width, and backspacing for your application.
With the data harvested, we came to the following sizes for the wheels. For the front, we ordered an 18×10 rim with 6.5” backspacing. The control arm is the limiting factor here with width, though with fender rolling, it may be possible to go another .5” wider. In the rear, with the room gained from tubbing the wheel wells, we landed on 8×11.5 with 8.5″ backspacing. There were also measurements from our Schwartz chassis that we sent into Forgeline as well.
We made sure to include the hub measurements from the unsprung components as well – the 1.60″ tall front Baer brake hub, with a 64mm diameter, and 1.575-inch tall rear with a 61.5mm diameter. We worked closely with folks at Forgeline who helped guide us through the process. They really know their stuff and are a great partner when you’re trying to make sense of all the measurements. Their expert customer support really simplified the entire process.
When the rubber hits the tarmac, we went with Yokohama Advan A052 tires. We wanted the same overall diameter front and rear, which led us to a combination of 295/30/18 in front and 315/30/18 at the rear to match the maximum width wheels we spec’d. We could have gone to 12” wide rear wheels with a 335, tire but that would have created a less than the optimum combo of tires.
Yokohama sums it up by stating, “When you absolutely have to finish first, the competition-silencing ADVAN A052 is your one-way ticket to the podium. The tire’s Ultra-high turn-up and lower belt angle give ultimate handling on and off the track. Our new motorsports-inspired compound provides maximum wet and dry grip as well.” We agree, and they look cool too.
Some final thoughts on our journey to “shoe” Project Payback. Like the old saying, “measure twice, cut once,” we say, “measure three times, then place your order.” Test fitting a similar set of wheels and tires that you might have access to can alleviate some snags as well. We aren’t saying use an existing set of tire and wheel parameters, but a ” dry rehearsal” with an alternate set of wheels can suss out any issues if you are in the ballpark. Old cars have been run for decades and there are many measurement variances from car to car. Be sure to aggregate size, diameter, and backspacing data from your specific car when ordering wheels.
So for now, that’s the latest addition to the Project Playback saga. We think we hit the bullseye with our new wheels and tires and couldn’t have pulled it off without the high-quality components we are working with. We love how the car is shaping up and we can’t wait for more progress as the build inches forward. If you want to catch up on this Pro-Touring monster, be sure and go here for all the previous chapters. In the meantime, stay tuned for the next installment of our 1968 Pontiac GTO, Project Payback.