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Wheel and Tire Fitment - Fit More Tire!Here's three easy ways to get the most wheel and tire your car can hold From the April, 2012 issue of Popular Hot Rodding By Christopher Campbell Photography by Christopher Campbell
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Elsewhere in this issue we’ve explored all the myriad ways in which you can ruin a car’s look by failing to consider all the elements that have come together to create a complementary look. One of the key elements is wheel and tire fitment—not just how much of either you have, but where it’s positioned under the car. You’ve seen the guys who get this wrong. From a sideview, everything may seem copacetic, but when viewed askew or from the front or rear, the rollers are either sticking out too far, or sucked inward toward the framerails. It’s all about perception of proper proportion and there are really two basic elements to consider: get as much wheel and tire width as will fit, and bring the whole package outward toward the sheetmetal as much as possible. You want to create the feeling that the rollers are using all of the available real estate in the wheelwells, no more, no less. Historically, that was a bit of a problem, since one-piece cast wheels are only available in whatever standard group of backspace options that manufacturer chooses to produce them in. They may have one or two that will technically fit a given car, but it’s guaranteed that there will be a trade-off. You either won’t get as much width as you could, or it could have that unmistakable “generic” fitment. If you know what you’re looking... If you know what you’re looking for, you really only need a ruler and a yardstick or tape measure to get your numbers. Here Zak Kingsland of Boze Wheels uses them to create a “T” from the wheel mounting surface and checks the most obvious consideration: inner wheelwell to the quarter-panel lip. The ’76 housed roughly 11 inches of cavern at peak, but to account for tire and wheel flex under cornering loads we need to leave about .5 to .75 inch of clearance on each side. Also, note the shape of your wheelwell and how much suspension travel you need as that may affect the numbers. Nowadays, two-piece wheels are common and come in a wide array of styles and prices, and thanks to the centers being manufactured separately from the rim, the number of backspacing options skyrockets. We knew we wanted something with a little attitude to give the EcoNova more personality than the chrome rallies could, so we gave Zak Kingsland from Boze Wheels a call to figure out what to use. Boze has a huge assortment of styles available, which is key for matching an oddball body like our ’76. Plus, Boze is local to Bodie Stroud Industries where the EcoNova currently resides and they regularly do business together, so he volunteered to swing by and show use the finer points of what to consider when ordering custom wheels and three unique ways to do it.  It’s critical to remember...  It’s critical to remember that on most cars the uppermost peak of the wheel lips is usually the area of greatest clearance. As Kingsland rotates the “T” forward the well lip rolls inward toward the rocker, and the clearance drops quickly down to 9.5 inches. However, by referencing the radius of our planned 25.5-inch combo on the yardstick and where we expect the tire to tuck inside, we discovered that the EcoNova’s long oval wheelwells allowed for plenty of clearance before rolling inward.  Here’s where it gets a little...  Here’s where it gets a little tricky with the rulers; the first place a tire will make contact during a turn on a subframe-equipped GM car is on the rearward side of the subframe itself. With the discs pointed straight ahead, Kingsland noted where the two intersected, then we slowly turned the steering wheel to full lock and measured how much more backspacing could safely be packaged.  The hub diameter may or may...  The hub diameter may or may not be an important measurement to have, depending upon the car and the wheels you opt to run. For hub-centric wheels, it’s a much more critical number. For our Nova, we’re more interested in confirming clearance in the wheel.  While it’s not an issue with...  While it’s not an issue with our stock GM rear drum brakes, the front discs and their hefty hub need to be measured to make sure they’ll fit beneath the center cap. In our case, the 2.8-inch hub height would require a specific centersection for the wheel that has extra depth. Also note the step on the hub; we need the measurement at the fattest point to ensure clearance.  If you need to confirm the...  If you need to confirm the bolt circle, the ruler will tell all as well. Simply measure from the center of one stud to the rear of the stud that is almost directly across from it. You can also measure from the center to center on the studs and multiply by 1.05. Either way will get you close enough to make the answer obvious.  Up front, we start with the...  Up front, we start with the same clearance measurements to get a baseline. Of course, the front wheels do much more than just roll along like the rears.  Brake templates are downloadable...  Brake templates are downloadable from companies like Baer Brakes if you’d like to be very exact. Here’s how to quickly check whether the wheel you’re considering will clear your intended brake package. Neither diameter nor caliper size will be an issue with our 11-inch discs. If you’re running the good stuff, Boze has special forgings for Baer, Brembo, StopTech, SSBC, CPP, Wilwood, and AP Racing.  For a starting point, Kingsland...  For a starting point, Kingsland measured the backspacing on the 15x7 rally that came off the car, since we knew it cleared with no issues. It was 4 inches dead-on.  Here’s what the filled-in...  Here’s what the filled-in Boze spec sheet looks like. These are downloadable from their website.  An all-in-one wheel diameter,...  An all-in-one wheel diameter, width, and backspace, and tire-profile—measuring device, the Percy’s WheelRite is a useful tool that’s cheap at SummitRacing.com.  Here’s how it works. When...  Here’s how it works. When bolted onto the wheel mounting surface, the sections of the WheelRite are slid to create the dimensions of the wheel. The wire across the top simulates the width and aspect ratio of the tire you want to run. We went for a 245/40 on an 8-inch rim and rotated the WheelRite around inside the wheelwell to check for subframe clearance. Looking good so far.  Though it’s the priciest and...  Though it’s the priciest and the most complicated, our favorite tool is the Wheel Fit from Wheel Works.  When assembled, the Wheel...  When assembled, the Wheel Fit will not only allow you to determine wheel diameter, width, and backspace, it’ll also hold the actual tire you want to run. The beauty here is being able to really see exactly where the issues are going to arise and what needs to be considered.  Using a spare 275/40R18 from...  Using a spare 275/40R18 from Bodie’s stash, Kingsland mounted up the Wheel Fit to do a near real-world double check of the clearances he had measured previously. He was dead-on, no adjustments necessary.  Here’s what all that work...  Here’s what all that work was for; a set of awesome looking Boze Pro Touring wheels in 18x8 and 18x9. It’s hard to match the ’75-79 Novas with a custom wheel, in our opinion, so we opted for a European touring style that would add some aggression to EcoNova without being overly flashy. These hit on all points, plus the multi-spoke design is strong and ready for the sticky 275-series Nitto NT-05 tires.  Mounted on the EcoNova, everything...  Mounted on the EcoNova, everything clears exactly like we planned, and looks even better in relation to the sheetmetal.  Oops, the Boze Pro Touring...  Oops, the Boze Pro Touring wheels look amazing on the EcoNova, but we’ve violated one of our 13 Sins Of Stance with a “Floodwater” look! That’s to be expected with stock springs and taking a couple hundred pounds off the nose with the E-Rod LS3. No sweat, it’s nothing a shorter set of springs won’t fix.  Up front, we confirmed that...  Up front, we confirmed that our measurements did allow for the room we needed to turn lock-to-lock without interference. We’re right on the money here and wouldn’t want to be any tighter than this.
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