On 22 April 1922, the Italian company "Rudge Whitworth Milano" was established in Milan, with a share capital of 1,200,000 lire. The owner was Carlo Borrani. The company was located at Via Ugo Bassi 9, and its activity was the production and commercialisation of wheels for cars, motorbikes and cycles.
This was the official beginning of the remarkable Borrani wire wheels story. Production started with a licence of Rudge Whitworth from Coventry, Great Britain, which had registered a patent for mounting a wheel on a hub by an unique splined drum, fixed by one central lock nut. This enabled an easier and faster mounting and dismounting of the wheel.
This also aroused interest from the most important racing car constructors. Just 12 months after Rudge Whitworth Milano commenced business, Alfa Romeo, Auto Union, Bianchi and Lancia started to equip their racing and deluxe cars with Borrani wheels.
Later in the 1930s, the company changed its name to "Carlo Borrani SpA". During this same period, Borrani started to experiment with light, rigid aluminium rims to replace the usual steel rims.
In 1955, the premises in Via Bassi became inadequate for the rising monthly production volumes that increased from 1,000 to 1,200 and then to 1,500 in the next 6 years. The company again changed its name to "CMR - Construzione Meccaniche Rho SpA" and moved to a new location. The production of wheels went on under the Ruote Borrani Milano trademark.
Ten per cent of production was devoted to racing cars. Ferrari was the best customer of Borrani at that time. This alliance was not accidental, as in 1924 the young Enzo Ferrari ran and won the Acerbo Cup in Pescara with a car equipped with Rudge Whitworth Milano wire wheels.
Borrani also became famous in the motorcycle world as supplier of renowned manufacturers Benelli, Gilera, Guzzi and MV Agusta. While among car makers, even Ford purchased the rims for the first version of its mythic GT40 from Borrani and used them on their Le Mans race cars. Thousands of national and international victories were achieved on Borrani wire wheels during this period.
After a successful period for wire wheels, the cast aluminium wheel gradually took over the market as first equipment. Looking for new ways, Borrani started to mount a pressed steel wheel disc in their existing aluminium rims. These 'bimetal' wheels, which were already produced as early as 1954, had their fair share of success and were mounted on famous brands such as Alfa Romeo, ASA, Abarth, Fiat, Lancia, Maserati and others.
All Borrani wheels were developed in close collaboration with the relevant car makers, as a complicated and sophisticated technical product. Borrani wheels in most cases formed an integral part of the car's homologation and were also extensively tested as such. Borrani wheels are unique products for the following specifications:
- materials used for hubs, rims, spokes and nipples
- dimensions and tolerances for hubs, rims, spokes and nipples
- technical specifications as hub threads rim shapes
All Borrani rims are identified by a stamped RW-code of four or five digits, the unique Ruote Borrani Milano stamping (there are several variations) and a stamped internal production number. The codification also applies to the hubs. All numerical codes correspond to technical and production documentation.
