Steel belted radial tires have been around since long before muscle cars gained popularity, but didn't see much use on performance vehicles (or any automotive applications) of the era because of safety reasons. Even though cars of the time would certainly have benefited from the strength and sidewall rigidity of a steel-belted radial, radials of the time were not able to withstand the heat of sustained high speed, and as this author can attest could blow apart doing body damage or at worst, causing loss of vehicle control at high speed. The causes of this problem have been debated, but in general terms the outer rubber plies of the tire would expand at a higher rate than the inner steel radial plies when heated by high-speed driving, eventually causing the outer rubber tread to separate from the tire. Modern radial tires are better engineered and speed-rated, ensuring they don't come apart, but back in the day radial tires were the cause of more than one wild ride or, unfortunately, often a totaled car.
Due in part to their construction from polyester, fiberglass, and rubber plies rather than steel and rubber plies, and also because of their bias design, bias-ply tires of the late '60s and early to mid '70s were a safer alternative for cars capable of 150 mph or higher top speeds. So for their time, tires like our Firestones were just about the best you can get, but compared to modern high-performance tires, they obviously come up a little short. For the purpose of looking stock, however, these wheels and tires really hit the mark. The wheels are powdercoated in the original argent silver color for a more durable finish than painted originals. Each wheel is also inspected for machining accuracy, concentricity, and run-out before being shipped.
We ordered our wheels and tires as a combo package, so the tires came mounted on the wheels, balanced, and filled with nitrogen. We also ordered all new trim rings and lug nuts for our wheels as well, and decided to deviate from a dead-on factory look in one area, the center caps. Seeing that Specialty Wheel offers a charcoal version of the correct cone-style center cap for our car, we decided the darker color would highlight the black stripes and spoilers on our car and ordered a set of four. The right wheels and tires will complement any car, and it's hard to beat the look of factory Mopar Rallye wheels.
On a technical level there's really nothing difficult about changing wheels and tires, meaning this is an improvement that any enthusiast can easily accomplish in an hour or so. We love the way our car looks and drives with the new wheels and tires, and also appreciated the ease of installation compared to the visual gratification of this project. Our B-body drives nicely and seems to handle well, though we won't drive too aggressively until we get to the track. If you're looking for a way to dramatically enhance the appearance of your vehicle, you should definitely consider new wheels and tires.

4 Our 15-inch Rallye wheels...

4 Our 15-inch Rallye wheels from Specialty Wheel are all new and likely better than original Rallye’s in terms of quality and precision. The wheels are powdercoated in the original silver argent color, and ready to install with the tires already mounted.

5 As far as technical projects...

5 As far as technical projects go, it doesn’t get much easier than bolting on center caps and snapping trim rings in place. If this is too much for you, we suggest having your wife or kids help.

6 We staggered our wheel...

6 We staggered our wheel sizing, ordering 8-inch width in the back and 7-inch wide rims for the front. Coker already had our tires marked as to their position on the car as well as the measured run-out of the wheel and tire.

7a With our new wheels and...

7a With our new wheels and tires ready to install, we removed the aluminum slotted rims that were on our Plymouth...

7b ...We like the slots but...

7b ...We like the slots but never really thought they matched the styling of our "fuselage" '71 B-Body.

8a After installing the lug-nuts...

8a After installing the lug-nuts and tightening them to factory specs with a torque wrench, we simply checked tire pressures and were ready to take a drive on our new skins...

8b ..We must admit there...

8b ..We must admit there isn’t a better looking factory wheel for a ’71 up Road Runner than a 15-inch Rallye.

9 We love the look of the...

9 We love the look of the Mopar Rallye wheels and Firestone tires on our Road Runner, and look forward to running some respectable elapsed times while our car appears stock. We’re also enjoying a smoother ride thanks to our new Coker tires and wheels. mm