Riding Pirelli’s Latest: the New Pirelli Diablo Rosso IV

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Pirelli’s Diablo Rosso IV employs different compounds and constructions based on tire size and application. (Pirelli/)

Almost 20 years ago, Pirelli introduced the Diablo series, the first of what would become an entire family of high-performance radial tires. In 2002 the Diablo replaced Pirelli’s previous premium radial, the Dragon, by taking the experience Pirelli had gathered from the Dragon and improving upon it with technology designed to increase the tire’s structural geometric stability. A new zero-degree belt constructed from spiraled steel wire made the tire more stable, which translated into superior high-speed cornering ability, better braking performance, and higher speed loading.

The original Diablo gave birth to a full range of radials, and today Pirelli offers them in five product lines: the “pro sport” Diablo SBK and Supercorsa SC; the “amateur racing” Diablo Supercorsa SP; the “road and track” Diablo Rosso Corsa II; the “road sport” Diablo Rosso; and finally, a line of Diablo radials for scooters.

Feedback From the Track

Racing is a demanding test bed that produces results quickly. As the sole tire supplier to the World Superbike series, Pirelli gets plenty of feedback from the best in the sport, and the new Diablo Rosso IV benefits from this. As the successor to the top-performing Diablo Rosso III, the Diablo Rosso IV is more specialized than any other tire in the class. So specialized, in fact, that the test and development team, led by Salvo Pennisi, has created specific technical characteristics for each tire size, front and rear.

I first experienced the Diablo Rosso IV while testing the latest MV Agusta Brutale 800 and Superveloce. My initial impressions were that the tires provided superior steering response and neutrality even on a wet track. The front Diablo Rosso IV was the big surprise, repeatedly demonstrating superior precision in a demanding situation as it pushed past 100 mph into an off-camber reducing-radius corner that requires respect and constant correction to stay on the line.

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The front tire’s superior dynamic response comes from the combination of the steel belt and the carcass structure. The structure features rayon cords, which are more rigid but more loosely woven (20 percent less compared to the Diablo Rosso III). This leaves more space for the rubber compound, and that in turn improves ride feel and precision, gives the tire more flexibility, and improves its damping properties. The tire’s performance under hard braking, even on a wet track, was another positive.

Specialized Construction for Each Tire Size

As we’ve mentioned, different tire sizes feature different constructions. For the rear sizes up to 190/50-17, Pirelli technicians applied the same structural solution, developing a carcass with rayon cords. These tires are more flexible and react more along their full profile. For the rear sizes from 190/55ZR-17 up, destined for the top-performing Superbikes, a new carcass featuring a three-stranded Lyocell structure has a significantly lower deformation ratio than normally seen in a road tire. This innovative Lyocell carcass is a direct beneficiary of Pirelli’s World Superbike experience, and offers a greater capability to absorb high-speed cornering loads.

Learnings from World Superbike were incorporated into Pirelli’s Diablo Rosso IV tires. (Pirelli/)

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The Diablo Rosso IV series also features new profiles that have been developed together with a new tread, a pattern designed to better channel water when riding in wet conditions. New compounds now feature full silica dispersion to increase wear resistance and wet performance. Front and rear tires in sizes up to 190/50-17 use a harder compound at the center and a softer compound on the sides, while sizes from 190/55-17 up feature three-compound construction: a hard central band, intermediate full-silica compound on the intermediate bands, and a softer full-black-carbon compound on the shoulders.

The Rosso IV front tire comes in three sizes (110/70-17, 120/60-17, and 120/70-17), while the rear comes in seven main sizes (150/60-17, 160/60-17, 180/55-17, 190/50-17, 190/55-17, 200/55-17, 200/60-17).

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