Sampling Nearly All Of Pirelli’s Motorcycle Tires In Two Days

A Sicilian symphony.

Tire testing in Sicily
Getting the power to the ground and maximizing a motorcycle's performance potential comes down to the tires. Cycle World heads to Sicily for some real-world testing.Jeff Allen

Although it's hard to tell by looking at them, those black rubber hoops that your motorcycle rolls on have evolved dramatically in the past decade. And they have to: Faster bikes with more power, complex rider aids, and ever-improving suspension and brakes enable riders to go farther with greater comfort and performance than ever before. Tires are expected not only to keep up with all this but to enable the overall progression of motorcycle performance.

They are as key to the overall systems as can be because—preferably—those contact patches are the only place your motorcycle touches the road. The best tires today offer near-peak levels of grip, hot or cold, wet or dry. So while tires aren't as glamorous as the spec sheet of a Ducati Panigale V4, they are no less impressive.

Especially the secrets they hold inside that make better riding life possible. We got special insight into all this during a trip to Pirelli’s proving grounds in Sicily, where we sampled most of the company’s tires. We roosted across sand washes and up lush island hillsides on the off-road-ready Scorpion Rally STR and Trail II duo, then burned rubber on Pirelli’s road-going offerings.

Pirelli Scorpion Rally STR and Trail II tires
Before the street, we rallied across the hills and washes of Sicily on Pirelli Scorpion Rally STR and Trail II tires.Pirelli

The, ahem, peak of our trip was rallying to the snowcapped top of Mount Etna rolling on Diablo Rosso IIIs. But we also ripped around the retired—but forever gorgeous—Targa Florio road course on machines shod with Angel GT II touring tires. After that, we upshifted to sport- and naked bikes rolling on the Diablo Rosso Corsa II and the ultrasticky Diablo Supercorsa SC at the ultrafast Autodromo di Pergusa.

Diablo Rossa III tires
Pirelli’s Diablo Rossa III tires took our sporty naked bikes up the switchback roads of Mount Etna.Pirelli

“Competing in all segments requires constant work and a diverse operation,” says Silvio Frare, product manager of Pirelli’s moto division in Milan.

“For typical motorcycle tire R&D, there are four main technical phases,” he says. “The first is the central research and development. It’s our engineer in the headquarters. He is sort of the orchestra director.

“The second important figure is the blend,” Frare adds. “It’s just like making a sandwich. You decide what process you will use in making the cheese, for example. And you can decide which process you will use to bake the bread. Once you put it together, you make the sandwich.”

tire production
Pirelli Moto Division Product Manager Silvio Frare describes tire development like making a sandwich—ingredients and construction are key.Pirelli

This “sandwich-making” process is perhaps the most complex, and for precise control the once-manual operation has become automated.

“Once for example, you were manually laminating the textile fibers and the rubber of the textile fiber,” Frare says. “This process went progressively more automated. This is one of the first things we started to do back in the 1980s. Now we put the raw ingredients on a table and you will receive the ‘baked’ tire. Of course, you need someone who controls these processes and checks that the parameters are correct.”

steel belt applied to insure quality
Automated processes makes for a higher-quality tire. Here the steel belt is applied at a nearly zero-degree angle.Pirelli

He goes on to explain that advances in and control of the process allows more finely dispersed ingredients in tire compounds.

“Imagine a sponge made up of large stones,” Frare says. “If you scrub it on a surface, you will progressively lose these large stones. So the risk is that you wear it out quite quickly.”

He says that by essentially making the elements of the tire smaller and thinner, the amount of material you lose when you scrub it against the ground is reduced and therefore lasts longer and wears more uniformly. This also facilitates a stronger structure, because more individual particles can form more chemical bonds when measured pound for pound against older processes.

The method used to “cook” the compounds is yet another critical factor, as is the variation of temperature applied during final curing.

“We are not simply scrubbing and mixing thinner and thinner particles,” Frare adds. “The key is to ensure slow, controllable parametric mixing where the right ingredients can enter the mixing process at the right point, without risk of overheating. This is one of the best processes developed by Pirelli in recent years.”

Following these first two steps, prototype tires are then thoroughly tested in a lab setting at Pirelli’s Milan headquarters to ensure the tire meets homologation and legislative requirements, as well as demonstrating the hoped for performance characteristics.

The fun part comes fourth, at least for us rider types: outdoor testing, which is basically what we got to do on our rapid-fire, 17-bike, two-day rip all over Sicily. This is where Pirelli’s real-world testing is conducted, thanks to the island’s ideal mix of terrain, weather, and often slick, soot-covered asphalt. There is a large dedicated off-road test facility, as well as the Pergusa racetrack, which Pirelli leases for exclusive use from the city.

Track testing at Autodromo di Pergusa
Track-testing the Diablo Rosso Corsa II and Diablo Supercorsa SC was done at Autodromo di Pergusa.Pirelli

You can thank the active volcano that is Mount Etna for making Pirelli’s outdoor testing “lab” so interesting, challenging, and beautiful. Our trip to sample essentially the whole tire lineup from dirt to asphalt racetrack demonstrates how far tires have come, and how quietly integral to overall performance they are. Black rubber “sandwich making” is sure to evolve even more.