In the first installment of our Pirelli tire testing adventure we rode motorcycles on the chaotic streets of Sicily, Italy to experience first-hand how Pirelli engineers its street bike rubber. Make sure to read the Testing Pirelli Street Motorcycle Tires in Sicily feature to see what happened. In Part 2 we visit its top-secret Siracusa proving grounds to understand how its tires behave on the racetrack.
Situated in the southeastern part of the island, the Siracusa facility is one of the circuits where Pirelli assess the performance of its road and track tires. The circuit was built in the ‘60s and actually held Formula 1 car races. Nowadays, it looks abandoned with crumbling stone walls set amongst overgrown vegetation. The dilapidated surroundings give way to a rough, bumpy, and broken pavement surface that just so happens to be perfect for tire testing.
The course is 3.18-miles in length and features a variety of different surfaces that help replicate the most severe road conditions. There are two straightaways taken in fifth gear on a modern liter-bike (170-plus mph). Most of the braking and acceleration zones are bumpy (even more so than Southern California’s ultra-bumpy Buttonwillow Raceway for comparison purposes) and even have chunks of pavement missing in some spots. If that isn’t enough, an assortment of bends with patchy asphalt work make things even more treacherous all in the name of research, allowing engineers to dissect the performance of the tire in a range of scenarios.
As we mention in Part 1, Pirelli has a fleet of motorcycles it uses to test the characteristic of its rubber. On our visit it had a pair of crossplane-equipped Yamaha YZF-R1 and a K7 generation Suzuki GSX-R1000 outfitted with its top-of-the-line street/trackday tire as tested in the recently published Pirelli Diablo Supercorsa SP Tire Comparison Review. The SP is designed for riders seeking true racetrack-grade grip and carcass feel with the consistency and quick warm-up time of a conventional street tire.
(Above) The surface of the Siracusa test track is rough and bumpy which makes it ideal for testing tires. (Center) Pirelli’s Siracusa proving grounds was built in the 1960s and held Formula 1 car races. Its dilapidated surface is now perfect for tire testing. (Below) The 3-plus mile track is divided into different sections in order to evaluate different aspects of tire performance.
The track is divided into sections and cones are placed strategically forcing the rider to utilize certain segments of the pavement. Each area is designed to work a particular component of the tire. From turn-in feel and bump absorption to edge/drive grip and stability. This is done in order to allow engineers to fine tune individual aspects of the tire’s performance.
I’ve always wondered why Pirelli’s DOT-labeled Supercorsa race tires feature a more flexible carcass construction compared to other brands, but after putting down some laps around the exceptionally rough circuit it suddenly makes sense. This construction offers improved bump absorption and allows the tire to remain in contact over pavement irregularities.
While the SP feels stiffer than the race version, it still has a bit of give in it which still provides an elevated level of feel at lean and when you’re accelerating hard on the gas off the corner. The tire also feels very neural. The exterior profile isn’t overly pointed or too sharp and the tires offer a predicable level of feel as the motorcycle transitions from straight up and down to high degrees of lean. The amount of outright grip afforded by the SP is downright astounding. Plus, traction comes early with the tires building heat within just a few turns. On the flip side, the tires don’t overheat even during a hard run, instead offering a steady level of grip/feel and never getting that “greasy” feel—a telltale sign of tire overheating.
In spite of Siracusa’s dilapidated surface, the track was actually a blast to ride and gave me some insight on why Pirelli engineers its tires with certain characteristics, including excellent bump absorption, stability and neutral steering feel. Tune to Part 3 in which we visit its Vizzola test track located near Milan where it does its primary wet weather testing.
The Pirelli Diablo Supercorsa OEM Replacement Front Tire and Pirelli Diablo Supercorsa OEM Replacement Rear Tire are available at Motorcycle-Superstore.com
MSRP: $238.95 (front) and $301.95 – $382.95 (rear).