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95 years ago, Ettore Bugatti was the first to cast aluminum molds, brake drums, spokes and wheels he had designed himself in his foundry in Molsheim. Bugatti further developed the idea of the aluminum wheel and registered over 500 patents.
These include the patent “Improvements to vehicle wheels with cooling discs” from 1924. Then, in 1933, the “elastic wheel whose wheel rim is cushioned against the wheel body in the radial and axial direction”.
But even before him there were many inventors who also independently dealt with the topic of "aluminium". Just like the inventor Charles Martin Hall and the chemist Paul Hérout. They developed an electrolysis process to produce aluminum.
Racing car designer Harry A. Miller came up with the idea of manufacturing aluminum wheels as early as 1920. Although he patented his invention at the time, he never produced wheels.
Bugatti Type 35 racing car uses aluminum wheels for the first time
But back to Bugatti. Ettore Bugatti's aluminum wheels were not used until 1924, on the Type 35 racing car. The cast aluminum wheels consisted of eight flat, wide spokes, a removable wheel rim and an integrated brake drum.
They were to lead the Bugatti brand to victory in the 1924 French Grand Prix. Unfortunately, several racing cars failed due to technical problems. It wasn't the fault of the new aluminum wheels, but of the tires that were mounted. Incorrect vulcanization causes the tread of several tires to detach from the carcass.
Ettore Bugatti is sticking to his innovation
[dropcap size=big]35[/dropcap]The Type 35 Bugatti wheels with cast, ribbed brake drums offered many advantages. The ring mounted on the outer wheel rim with initially 32 and later 24 screws prevented the tire from jumping off even when cornering at high speed. The drivers were able to achieve higher cornering speeds. The wheels could be changed more quickly in the pit lane thanks to a central attachment.
Lower weight compared to steel rims
The handling of a vehicle changes as the unsprung mass decreases. The lower weight compared to the steel rims is also decisive. With the aluminum wheels, the Type 35 could be steered more easily and precisely, braked better and had more comfortable suspension than comparable racing cars. As a result, the drivers drove longer, faster and with more concentration in the races, which often lasted several hours or even days.
Horseshoes and aluminum spokes - Bugatti's trademarks
Bugatti will produce seven different types of aluminum wheels over the next few years. For the racing cars Type 35, Type 39 and Type 51, the French company makes three different versions. The horseshoe-shaped radiator grille and the cast wheels with their eight wide aluminum spokes became Bugatti's hallmarks.
Just like 95 years ago, weight is the deciding factor today
The current rims of the Bugatti Chiron and Bugatti Divo consist of a forged aluminum alloy. In a special process, both wheel sides and cavities are finely milled. You get a minimum weight with maximum stability and rigidity. The wheel is then powder-coated and burnished.
Instead of eight spokes, Bugatti is currently using a five-spoke Y layout. This optimally distributes the forces to the five wheel bolts. The lightweight wheels withstand even extreme pressures and forces even at speeds up to 400 km/h and above stand.
50 times per second
At top speeds, a tire rotates over 50 times per second. In the process, forces occur on the tread that correspond to around 4.000 times the acceleration due to gravity (g = 9,81 m/s2). The weight of the valve alone increases from 18,3 grams to around 55 kilograms when driving at full throttle.