The Innovations of the 1930s: The Stella Bianca and Extra-light DD Rims
In the 1930s Pirelli concentrated in particular on the world of racing and speed, with the Superflex Cord now becoming the Stella Bianca: the tread pattern was more complex and sporty and the five-pointed star of the Pirelli brand was coloured white. 1932 brought the Supersport, a full line of racing tyres, initially with the basic tread and later with the Stella Bianca pattern. This was the Stella Bianca Corsa line. The 1930s turned out to be particularly fruitful for Borrani too: a rim specially designed for racing came out in 1931, named DD after duralumin, the light alloy used. This material was lighter than steel, and meant that the wheel could be made perfectly round, with a special assembly pattern with external spokes on three rows, making the wheel more resistant and its response to direct perpendicular forces more elastic. The “magnificent” DD light alloy wheels, as an advertisement proclaimed at the time, were Borrani’s flagship product.
Our Foundation has preserved one rare Supersport tyre from that period with a Borrani DD rim, probably made for Auto Union, a German car manufacturer founded in 1932.


In the 1930s Pirelli concentrated in particular on the world of racing and speed, with the Superflex Cord now becoming the Stella Bianca: the tread pattern was more complex and sporty and the five-pointed star of the Pirelli brand was coloured white. 1932 brought the Supersport, a full line of racing tyres, initially with the basic tread and later with the Stella Bianca pattern. This was the Stella Bianca Corsa line. The 1930s turned out to be particularly fruitful for Borrani too: a rim specially designed for racing came out in 1931, named DD after duralumin, the light alloy used. This material was lighter than steel, and meant that the wheel could be made perfectly round, with a special assembly pattern with external spokes on three rows, making the wheel more resistant and its response to direct perpendicular forces more elastic. The “magnificent” DD light alloy wheels, as an advertisement proclaimed at the time, were Borrani’s flagship product.
Our Foundation has preserved one rare Supersport tyre from that period with a Borrani DD rim, probably made for Auto Union, a German car manufacturer founded in 1932.