CAR Associate Editor Gareth Dean tells the story of how Bugatti pioneered the first aluminium wheels for its 1924 Type 35. Despite the concept of the wheel dating back to the prehistoric ages, the use of aluminium alloys is quite a bit younger. At its core, the alloy wheel consists of a mixture of metals and other elements to provide greater strength and a lighter mass, thus improving the performance of the car that uses them.
Although aluminium wheels became popular in the 1960s, the first recorded use of the concept came about in May 1924 via a patent registered by Ettore Bugatti. Titled, “improvements relating to vehicle wheels with cooling discs”, the patent provided his Type 35 racecar with cast aluminium wheels with eight flat and wide spokes rather than the multiple thin spokes that were used on its previous examples. Furthermore, the wheel rim was removable and housed the entire brake drum. The reason for this was to improve cooling by having the design double-up as a heat sink.
While it saved weight, it was noted that the car’s smooth ride had become compromised. On its debut race appearance at the Lyon Grand Prix, all examples of the Type 35 retired however, this was not because of the wheels but rather the incorrect molding process of the tyres which caused the tread to separate from the fibres. Once this issue was sorted, the Type 35 went on to become an unstoppable racecar up until the 1930s.
Other than the Bugatti Type 35, there were four other cars that paved the way for the concept of the wheel as we know it today. In 1902, the Thomas B, Jeffrey Rambler was the first production car noted to offer a spare wheel, during a time where paved roads were not yet a luxury for motorists. Eight years later, the Austin 10 HP became the first car to move away from wooden wheels and adopt a pressed steel design.
Some years later in 1971, the Citroen SM rally car co-developed with Michelin, revealed the resin-based wheel which weighed half the mass of the steel unit and was offered on the production car as an option the following year.
In 2015, the Ford Mustang Shelby GT350R became the first mass-produced car to offer a carbon fibre wheel option that offer decreased mass and a 40 per cent reduction in rotational inertia which improves input and overall handling characteristics.