GM will offer magnesium wheels on the Cadillac CT4-V Blackwing and Cadillac CT5-V Blackwing. These pictures show the smaller of the two ultra-high-performance luxury sedans fitted with the unique rims.
The Cadillac CT4-V Blackwing is painted in Wave Metallic blue, which contrasts nicely with the gold magnesium wheels. From a functionality standpoint, the advantage of the mag wheels is magnesium’s exceptionally high strength-to-weight ratio, which allows them to be lighter than the stock aluminum items while remaining equally tough.
That lightness should be beneficial to the car’s handling, though in most driving conditions the effect will be minimal. There may also be an improvement in straight-line acceleration, not simply because they reduce the overall weight of the vehicle but because they offer less rotational inertia for the twin-turbocharged 3.6L V6 LF4 engine, rated at 472 horsepower and 445 pound-feet of torque, to overcome. The lower unsprung weight might be seen as a disadvantage because it usually leads to a negative impact on ride quality, but magnesium’s high damping capacity should sort that out. The metal can convert movement into heat (rapidly dissipated by the surrounding air) instead of transferring it to the cabin, which will help smooth out the ride.
Magnesium wheels are sometimes thought of as being dangerously flammable, and this would certainly be the case if they were constructed simply of the pure metal. However, the wheels are made of magnesium alloy, which does not burn. An approximately analogous situation is that eggs used as ingredients for cakes never hatch into chickens.
It is uncommon for magnesium wheels to be offered on production models due to their expense – for example, they are unlikely ever to be an option on entry-level models such as the Chevy Trax or Buick Encore. However, they are sometimes used on high-performance road cars, and are almost universal on professional competition vehicles, such as the Cadillac DPi-V.R race car.
Besides the functional performance qualities, the wheels also have a gold-bronze hue, making them distinctively unique. It’s currently unclear how much GM will charge for the mag wheels on the CT4-V Blackwing, but we do know that they will not be available for the 2022 model year.