Tire Review – Pirelli Diablo Rosso Corsa 2

Tire Review – Pirelli Diablo Rosso Corsa 2 Tires
Story and Photos by Mazlow Petosa

One thing I learned after moving to California is that ‘desert’ doesn’t mean it’s going to be hot, it just means that you’ll get extreme weather. In the middle of February that means cold, and this year it has meant rain. My first track day of the year was 54 degrees. Rain was on the forecast before and after, but not on Friday. Conditions changed daily leading up to Sunday, and I seriously considered throwing in the towel. Thoughts about money and how big your balls have to be to race in the rain passed through my mind… But then I caught a glimpse of my 2007 Honda CBR600RR. It was perfect. In preparation for the track day, I had changed the oil and filter, installed new brake pads, changed the brake fluid, checked the coolant, and put on a new 520 chain and sprocket kit (+1 rear). More exciting than all of that however, was a fresh set of Pirelli Diablo Rosso Corsa II tires that would carry me to my personal best recorded lap around Buttonwillow Raceway.

To me, track riding is the ultimate form of motorcycling, so I decided to persevere. I consider myself an average-skill track day rider. I have completed Level 1 of California Superbike School and done several track days in B group. For now, I only have one bike and it must be a passable daily rider during the week while living up to its supersport heritage on the weekends. My tires must perform accordingly.

After smelling rubber in my closet for months, I finally slapped them on and prepped my bike for the track. It was a cold and wet morning, but nobody let it dampen their spirit. Full of excitement for my first rip of the year, and with ever increasing respect for the professionals, I pulled into the wet pit lane. Of course, right before I went out on track, it started actively raining. The entire day continued with this pattern, despite A group’s best efforts to carve out a line for the rest of us.

Track riding in the rain is like driving with aerodynamic grip. Shocking grip becomes available at a scary speed. Being a DOT legal street tire, the Rosso Corsa II was designed for inclement weather. The tire sipes are located within 35 degrees of center, maximizing the amount of water evacuated from the contact patch at reduced lean angles. Rapid heat up and optimizing tire feel throughout turn in were also considered during the tire design. Worthy attributes, as chemical grip and comfort become even more important in bad conditions.

The on-site tire provider recommended wet settings of 31 psi in front and 28 psi for the rear. With any kind of track riding, comfort is everything. If you feel the tire working underneath you, it inspires the confidence to explore your own limits. Heat builds gradually over about three laps, with the difference over cold being pretty drastic. Initially, I found myself having to be most gentle with bar inputs. The front would wander when I was too aggressive, especially over the imperfect surface of Turn 2, also known as Off-Ramp. Given my limited dirt experience I found this unsettling. However with practice came comfort, and with comfort came smoothness. Smoothness led to grip as I simply allowed the tire to do its job. My confidence in the front grew throughout the day, and I began to experiment during mid-corner and corner exit. “Hang off, stand the bike up, and smoothly power out” rang like song lyrics stuck in my brain as the tires continued to deliver everything I asked of them. Once the desired lean angle is achieved, mid-corner grip is immense. With the chassis settled, the tire sipes went to work and held a line predictably.

The rear tire had similarly surprising levels of grip. I was always careful to begin standing the bike up before grabbing a handful, and this simple process allowed me to progress at my own pace. I could feel my brain holding me back more than the tires, as is often the case when searching for speed. I never grabbed enough throttle to step the bike out, which speaks to the high margin of grip available compared my average skills. I finished the day with confidence in my own abilities. Sensations coming through the bars turned from scary to recognizable, and eventually felt like less extreme versions of the same forces present when riding on dry pavement. Obvious of course, but to recognize this and apply it on track was a huge step forward for me.

For those with newer bikes, the Rosso Corsa II is designed to optimize modern day electronic systems. Additionally, the Rosso Corsa II has a maximum lean angle of 52 degrees, four more than the original. Above 35 degrees of lean, rain sipes give way to a smooth tread that looks and performs like a slick. The shoulder compound is heavily based on Pirelli’s own Supercorsa, and edge stiffness was maximized for predictability. Multiple tread compounds were a huge leap forward in DOT tire technology, but the rain left me lacking any information on how the Pirelli’s party zone performed. In the name of science, I went back to Buttonwillow twice more to investigate.

I set the front tire to 30psi, and pulled out to see what these Pirellis could do. I generally refrain from passing on the out lap order in to keep myself under control while the tires come up to temperature. These tires do not require warmers, but they did require two full laps before I felt ready to explore. Early attempts to brake hard and turn in quickly led to a stiff feeling front tire, a gentle reminder that I was jumping the gun. A little patience is rewarded with the tire feeling progressively more responsive and the providing the confidence to push.

I began to confidently brake deeper and deeper into Sunrise, the hardest braking zone at Buttonwillow. My forks quickly ran out of travel, and bounced through turn in. A half turn of compression and rebound gave me the control I was looking for, and my braking zone got deeper until my brakes couldn’t handle the punishment. The tire however took everything I could throw at it, building confidence along the way. Increased stability from the chassis also allowed me to send and receive more input through the front. Carrying lean angle with increasing speed over Phil Hill results in a lightness that feels like an approaching highside. After a few sessions, the sensation became manageable and, eventually familiar as the tire always found what it was looking for.

The rear tire inspired similar levels of confidence. Set at 26psi, higher corner entry speed and earlier throttle application became unachievable goals as the slick compound edge continued to stick. I ended the day comfortable enough to pick up the front wheel in transition coming down Phil Hill. The following near 100 mph left hander on to Drag Strip has some bumps that would cause the rear end to squirm and wiggle. Staying on the gas kept the chassis settled, and the tire was more than capable of handling the rest while I rocketed forward. Eventually, Aprilia Tuonos on Pirelli Supercorsas became limited by their riders as I would dance around them at Riverside and get the jump on corner exits.

On the street, I never rode hard enough to doubt if the Rosso Corsa IIs were up to the challenge. I went to explore the canyons twice, and the tires were more than comfortable at a spirited pace. Despite the harder center compound, I never felt a lack of grip and greatly appreciated the increased wear resistance. At the end of its life, the rear tire had worn down the shoulders more than the center, typical of a tire that was abused on track. Over three months of commuting, I was caught in the rain two or three times. With the confidence from my track day, I never doubted my chances of making it home. Overall, the rear tire survived a very busy three months, including seven track days of up to 160 miles, and about 2000 miles total. 2000 miles may seem low for a street tire, but over half of those were on track. Over the life of the rear, I have progressed comfortably into A group and my lap times reflect the confidence I have gained.

My fastest recorded lap in 2018 was a 2:16. I finished this test with a fastest recorded lap of 2:10. Race pace is under 2:00, so there was 6 seconds on the table, but I am happy with the improvement. When I nailed the turn in point as well as body position, I could feel the chassis hunker down to its happy place and the tires give that little bit extra. I knew I must be simply out of the way and allowing them to operate most efficiently. Ultimately, the Pirelli Diablo Rosso Corsa IIs resulted in peace of mind. They gently calmed my nerves while the devil shouted “You can do it!” in my ear. By the time I replaced the rear in June, my lap time had dropped to a consistent 2:08. Meanwhile, the front tire has plenty of life left to carry me through a summer of commuting.

Whether or not el Diablo has your best interests in mind is up to you.