Steve Baur
Former Editor, Modified Mustangs & Fords
May 27, 2014
Photos By: Courtesy Boze Forged

The Tire Of Choice

When choosing a tire for our Colt of Personality project, we started our research by looking at what many of the successful Optima Challenge cars were running. Falken's Azenis RT615K was a popular choice with that crowd and a number of the events winners were equipped with it. We plan to flog our filly at various track events, and many of them require a UTQG treadwear rating of 200 or better. We also have previous experience with the K's progenitor, the RT615, at Sebring International Raceway as well as on the street and were very impressed with its on-track qualities and street behavior.

The RT615K has been endowed with the aforementioned 200 A-A treadwear rating, along with an advanced compound for street and track use. The motorsports-inspired 8⁄32 tread design and solid center rib provides significant traction and sustains strong grip in dry conditions. The RT615K is available in 21 sizes from 14-inch to 18-inch, and we have picked out a P275/35ZR18 tire for the front, and a P315/30ZR18 for the rear. That's a lot of rubber to tuck under a first-generation Mustang, but the addition of aftermarket fender flares has afforded us a bit more room than what the stock quarter panels have to offer.

13. We knew we were going to roll the fender lip, and we had a half-inch of clearance between the tire and the control arm, but we may need to further modify the flare/fender to get the wheel/tire package to fit without any rubbing issues. We’ll cover those changes in our upcoming fender flare story.

14. While the Wheel Fit tool provided us with valid measurements for spacing and wheel width, Boze goes by its own measurement form, which we needed to fill out for both front and rear wheels.

15. The first measurement on the list is A, which is the distance from the hub-mounting surface to the inner fender well. Keep in mind that if you have something else that the wheel will come in contact with before the inner wheelhouse, such as the lower control arm or leaf spring, make sure you record that measurement instead and let the Boze folks know about it.

16. Measurement B is the distance from the hub surface to the innermost fender edge.

17. Measurement C is the distance from the hub surface to the front of the brake caliper. Here you can see we have a negative measurement, but that may not be the case in all instances and you can have separate measurements from front to back as well.

18. Measurement D is the caliper height, or the measurement from the centerline of the axle to the top of the caliper body. This will vary with brake drum, rotor, and caliper sizing.

19. Measurement E is the register or hub diameter and F is the height of it. This is important with any wheel selection as aftermarket parts can produce a register size that doesn’t fit the wheel, and excessive hub heights may require a taller pad or a taller center cap, if available.

20. Here you can see we measured the distance from the hub surface to the control arm. Boze recommends a minimum of a half-inch of clearance between the wheel and anything else; an inch of clearance is recommended up front where turning can move a tire around a bit more. When it comes to measuring for the front, it also helps to remove the shock and/or coil setup so you can move the mounted tire throughout its range of motion to ensure proper clearance.

Decisions, Decisions


Boze offers any of its wheels in 17- to 24-inch diameters and 7- to 15-inch widths. There's really something for everyone among the company's dozens of available designs, but for the Colt of Personality, we were set on a racing-inspired, mesh wheel design. We did receive a bit of email about going with a five-spoke wheel and larger side profile tires, but it's not quite the look we are going for.

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When we conceived the project and had Brockmeyer Designs complete the rendering, the Apex wheel (Photo 1) was Boze's latest offering and our choice for the project. Since then, Boze has modified the Apex design, turning it into the new Daytona model (Photo 2). Aside from the bolts in the three-piece version, you can see that the center of the wheel has been softened for the Daytona. Other options include the Mesh (Photo 3) and the Pro Touring (Photo 4), as well as Boze's latest offering, the Performance (Photo 5), which is the wheel they were building here in the photos. We haven't quite settled on a design since we've been sorting out the fender flares and wheel/tire fitment, but we certainly have plenty of options. Check out to see all of the other designs that are available.