What goes into making an F1 wheel, where every 10 grams of weight reduction counts? Impeccable precision and tedious optimization. Why the same technology of forged magnesium wheels is slow to find its way into the mainstream – both for racing applications and for tuning street-legal cars. It’s been mostly prohibitively high pricing and concerns of expeditious corrosion after a scratch. However, both of these factors appear to have been addressed with the latest available technologies.
FEA analysis – Formula 1 wheels (courtesy of SMW Engineering)
The multi-step forging process is defined by true high-tech metallurgy, where duly prepared bullet is subjected to extreme heat and pressure, resulting in a dense, durable material. Where maximizing strength is essential, a hydraulic force of 15,000 tons is irreplaceable for refining and controlling its grain structure. Magnesium has a more challenging hexagonal lattice formation, but when 15 million kilograms of force come down slowly (at 3 mm per second) on a magnesium billet, the metal has no chance to resist. It flows precisely into the desired shape, with all grains and fibers lining up as prescribed. Grain-flow conforms to the contours of the finished piece, whose job it is to deliver the very top performance, and to keep the pilot safe in the process. A wheel that is less than perfect is not an option. Top speeds are unforgiving; no room for error either by pilots or by metallurgical engineers working behind the scenes. The resulting state of the art represents the highest level of excellence.
The fibers line up directionally, providing for increased strength-to-weight ratio in the wheel segments where it is most important. It’s a dependable structure under pressure, having zero porosity. Magnesium alloys possess dozens of times higher damping factor than aluminum counterparts, thus reducing vibrations and insuring a better ‘grip’ of the road. And specific stiffness is higher as well.
These wheels made of high-grade magnesium alloys are ultra-lightweight – about 20% lighter than the very best forged aluminum wheels.
Forged wheels, while more expensive than their cast alloy counterparts, provide the ultimate in performance: better cornering, faster acceleration and improved braking. Drivers are become aware of what professionals have known for many years: forged wheels go the distance in ensuring top performance. In turn, high-performance vehicle manufacturers are turning to lightweight forged alloy wheels to increase driving agility through an impressive weight reduction in the wheel.
A forged wheel is about 40 percent stronger than its cast alloy counterpart. While most still believe these wheels are more appropriate for motorsport use, they do create an opportunity for substantial drive quality improvement, along with reduced brake and tyre wear and a lower risk of tyre blow-out.
These represent a clear example of a cutting-edge motorsports technology making its way into the mainstream, being an investment well worth considering.