Pirelli's Stella Bianca rolls new tire tech into old construction
The reborn Stella Bianca tire features modern rubber compounds paired with bias-ply construction and Pirelli's longest-serving tread pattern.
Though you can't always see it, tires are packed with technology that has made modern cars safer and faster than ever before. One of the most significant leaps forward was the change from bias ply to radial tire construction, and since then, the world hasn't really looked back. But there's still goodness to the old bias ply design, which Pirelli hopes to prove with its Stella Bianca tire, revealed Friday.
Bias-ply tires were commonplace from the 1910s all the way to the 1970s. The term "bias ply" refers to the way the tire is constructed, with the cords that make up the structure of the tire crossing over one another at 45-degree angles. This creates a very stiff tire with very different handling and aesthetic characteristics from modern radial tires.
That aesthetic aspect is essential, particularly on vintage exotics from companies like Ferrari or Bugatti . The tall, thin tire with a slightly bulging sidewall is critical to the look of these cars, and radial tires can't replicate that accurately. Unfortunately, because bias-ply tires have fallen by the wayside, they haven't benefitted from the advancements in rubber compounds and construction materials that radial tires have, until now.
Pirelli is resurrecting its Stella Bianca tire as part of its Collezione family. It's the first bias-ply tire that the company has made in over 50 years, and while it accurately recreates the looks and tread pattern of its namesake, the new version is much safer and better-performing. That's largely thanks to the introduction of silica and other materials into the rubber mixture, dramatically increasing performance in the wet and improving grip.
Pirelli's Collezione has typically made its modernized classic tires for very specific fitments, and we'd guess the Stella Bianca will be similar, though the tire manufacturer didn't immediately respond to requests for clarification. Given that the originals were sold with cars like the Jaguar XK120 and Ferrari 166, we'd expect to see these new Stella Biancas at concours events around the world.