Take a second and picture this: After far too many hours of traveling we’ve finally made our way to the Netherlands to test Pirelli’s all-new Diablo Rosso Corsa tire at the famous Assen TT circuit. Following a day watching the World Superbike boys race in utterly ideal weather (70 degrees and sunny), we come back to the track to ride the Monday after, all jazzed and ready to go, only to be greeted by the after effects of heavy rain that fell throughout night. Although a slight mist was still coming down the boys from Pirelli were eager to get us on track so we were suited up and ready to go in no time. Great: A new track, new tires, in the wet. This is going to get ugly, fast.
Not ones to shy away from their tire’s wet weather performance, after a mere two sighting laps behind Pirelli’s test riding staff they let us loose. I’m not going to lie; I was nervous, as I tip toed my way around the track. Assen is one of the fastest and most technically demanding circuits on the planet. Not a place you want to have an off, that’s for sure! But after being, for lack of a better term, a complete wuss for a bit as I learned the track and felt out the conditions, as the laps wore on and my confidence built up I managed to work my way to knee-dragging lean angles and quite high corner speeds – in very soggy conditions. And while it wasn’t fully wet, there were plenty of damp patches and standing water scattered around the track. Despite the adverse conditions, the Rosso Corsas dispersed the water with ease. And where the payment was dry, even with an ambient temperature that was maybe 45 degrees, outright grip was outstanding.
By the end of the first outing I was truly blown away. What I thought would be a white-knuckled crash-fest turned out to be an absolute blast, not a single rider in our group fell down. It may have been the most enjoyable wet session I’ve ever experienced, and it set the tone for the rest of the day…
Those Black and Round Things
Okay, so there’s a bit more to it than that. The science and development that goes into those ‘black and round things’ on your motorcycle is extensive. Where does Pirelli do their sportbike R&D? Where else: World Superbike. Despite it being a spec tires series, the Italian manufacturer is continually developing new tire solutions for the championship, which in Pirelli’s case then trickles down the consumer very quickly. For example, they used 48 different compound or construction tires in 2009 alone, supporting the series with eight rigs and over 5,000 tires per round in their seventh year of duty as the series’ spec tire.
Say hello to Pirelli’s R&D department team – The ultra-competitive and highly demanding World Superbike Series.
Pirelli could sit back and relax without worrying about any competition, but they don’t. They use World Superbike as an R&D tool. Of course, they also have a full development center with multiple test tracks in Sicily, where they complete both on-road and off-road testing. But there’s no question that every set of Pirelli sportbike tires owes a great deal of its performance to the men of WSB.
When designing the new Diablo Rosso Corsa (DRC) Pirelli set out to make the an “ultra-performance radial tire” which is “aimed towards today’s modern sportbike characterized by new technological features and electronic aids, such as ABS systems, traction control, suspension control and gear shifting systems.” In other words, this new tire was developed directly for the current crop of high-tech sportbikes. How did they do it?
Getting down to the nuts and bolts of what actually makes up the new tire, a 100% Carbon Black compound lowers the DRC’s rigidity, especially at mid-to-low temperature, allowing very fast warm-up. It also reduces the temperature difference across the tire’s surface for a very linear transition from one compound to the other on the rear tire.
The Diablo Rosso Corsa features a triple-compound rear construction; softer on the sides for grip and harder in the center for durability.
The rear features a triple-compound, or ‘3-zone construction’ as Pirelli calls it. This has now become standard practice among today’s leading sport tires and in the case of the DRC rear, it features SC2 racing compound rubber on the shoulders, derived directly from World Superbike and World Supersport, while a much stiffer and more wear resistant rubber makes up the center patch for long-distance street riding. Front tire compounding is also a direct descendant of WSB knowledge, aimed to produce the highest possible grip without losing tread stiffness.
To further improve grip is Pirelli’s Enhanced Patch Technology (EPT), another solution that was directly developed through WSB experience (starting to get the picture here?) and is said to optimize the tire’s contact patch at all lean angles, both road and track, for the maximum amount of allowable power transferred to the pavement.
Pirelli claims that in direct back-to-back tests with their own previous generation tire as well as those of the major competition – Dunlop Qualifier, Michelin Power Pure, Bridgestone BT016, Metzler Sportec M5 – they were able to extract at least 10 additional horsepower from the DRC. What do they mean by this? Through the use of data acquisition the Italian manufacturer says they can determine exactly how much power each tire is able to onto the pavement. This was measured at their controlled test track, on a control bike, with the exact same riding conditions for each tire. According to Pirelli, the new DRC exceeds all of them by “at least 10 hp.”
Even though tire grooving has been reduced from 14% to 7% as compared to the Diablo Corsa III, Pirelli claims that even with half the amount of overall tread the DRC actually performs better in the wet due to optimized design and positioning.
The new DRC features 25 patents within its design and construction, two of them with regards to its steel belting. An ‘H’-shaped bead was designed to increase sidewall stiffness and aid in additional support at maximum lean angles, while HPSC (High Performance Single Cord) technology utilizes a single cord winding of the tire’s entire steel belt that can be varied in depth and spacing throughout the design. This gives them the ability to change the structure of the tire from center to the sides without having to cut the belt, the middle being a stronger road-oriented wind and the shoulders featuring a more flexible racetrack-designed construction.
Tire grooving has been reduced from 14% to 7% as compared to the Diablo Corsa III that it replaces. Pirelli claims that even with half the amount of tread it actually performs better in the wet due to the design and positioning of the grooves. This Functional Groove Design (FGD) is supposed to combine a 100% slick tire on the shoulders for maximum grip with calibrated grooves in the middle that maximize contact patch. The transversal tread between the center section and the edges are designed to disperse residual water and provide maximum grip when leaned over both in the wet and dry. An additional slick area in the center puts more rubber on the pavement for added traction and stability when straight up and down.
The Atlas-spec is available in limited quantities and guarantees a 2-second drop in lap times. Road Test Editor Waheed already has five sets on order…
Another neat feature is Pirelli’s personalization system. They now offer custom stickers for your tire which can say basically anything one desires (within a set number of characters and not profane) in a variety of designs. Just log onto www.pirelli.com and for 5 Euros you can have them produce and deliver any personalized message you want, which then easily applies to an open space on sidewall of the tire.
Think of the new DRC as Pirelli’s do-it-all street and track day solution. At least that is what Italian brand wants you to think. Available in sizes to fit most modern sportbikes and in dealers or online retailers now, Diablo Rosso Corsa retail prices start at a hair over $450 per set.
A Dutch Day Out
When the invite came across my desk to ride the famous Assen TT circuit one thing quickly became apparent: I would make use of every ounce of power I have within the company to make sure I was the one going. Even if that meant just hiding it from everyone else! I didn’t care if I had to ride in the bay of a cargo plane for the 11 hours it takes to get there, it’s one of those legendary tracks that is rich with history. It looks absolutely amazing on TV and very few people ever get the opportunity to ride it. There was no way I was going to pass this one up!
As you know the first session was marred by wet weather and far-from-ideal conditions. Surprisingly, the new tire performed extremely well, and despite being a self-professed hater of wet tracks, I actually enjoyed it. Heat-up time in the dismally cold weather was quick, the tires dissipated water well in the damp patches and stuck like glue anywhere it was dry. Honestly, considering the wide variety of conditions, there probably wasn’t any better tire to be on.
Pirelli had a plethora of bikes on hand, from 600s to 1000s to V-Twins, for which to sample the new tire.
As the day went on it continued to dry out and by our third session it was totally dry and the tiniest hint of sunshine had peeked through the clouds. This provided us the opportunity to see how the tire performed when pushed to its respective limits of adhesion. Having also ridden Rosso Corsa’s predecessor to the the Corsa III, I was real curious to see if they had made inroads with regards to rear tire grip and corner-exit drivability.
While the previous generation front tire gave good feedback and was well shaped for predictable turn-in and overall rider feeling, the rear sacrificed true racetrack levels of outright grip for added durability on the street. Would this still be the case with the Rosso Corsa? They claim to now be using full race-spec SC2 compound rubber on the shoulders… and after ac ouple session shredding at Assen, we believe them.
We had a variety of bikes on which to sample the tire, from 600s to 1000s, Four-Cylinders to Twins, and the new rubber took the abuse and begged for more. Although we had a few issues with the astronomically high original “manufacturer recommended” tire pressures they were using (some of the bikes had as much as 50 psi in the rear to start the day), once dropped to 32 psi front and 30 psi rear both tires behaved remarkably well. The Diablo Rosso Corsa rear grip is leaps and bounds better than the Corsa III, requiring quite a handful of throttle on even a high-powered 1000 to induce any sliding. And when said sliding would take place it was controlled and predictable.
The fast and technical Assen TT circuit offers a wide variety of test conditions, providing the ideal place to put the new DRC through its paces.
Assen’s long straights lead into very high-speed corners which put supreme emphasis on front tire grip, especially the Turn 7/8 complex, which was updated slightly this year. After exiting the first-gear, parking-lot-tight Turn 5, you are wide open for well over a quarter-mile, clicking all the way through the gearbox with a slight kink in the middle called Turn 6. This leads into the mega-quick Turn 7. A right-hand corner with a slim entrance, when really moving you can enter at over 130 mph, with throttle pinned to the stop, knee fully planted on the ground and some serious lean angle. This then switches immediately back into a 100 mph left that requires two quick downshifts and a rapid change of direction. When done right it’s one of the most exhilarating and rewarding sections of racetrack I’ve ever ridden. But to do this correctly you have to be inch-perfect with your lines, and by no means is Assen a wide track. You must also have complete confidence in your front tire.
And while the new Rosso Corsa front tire worked equally well in the other sections of the track, this was the one area that really drove the point home. Never did I think a street tire could be pushed at that speed through such a hair-raising section of track. Had you told me before the day started just what was required to do that I probably would have kindly declined the offer. But after working my way up to it, by the second half of the day I could take nearly every bike, from 600 to 1000, flat-out through Turn 7. Truly amazing stuff from a street tire. In fact, I’d be hard pressed to put that kind of confidence in a three or four year old race tire.
Combine the new Pirelli Diablo Rosso Corsa tire and Suzuki’s ultra-versatile GSX-R750 and you have one very fun and easy-to-ride combination. Maybe even the ultimate trackday set-up…
The transition between the ripping-fast Turn 7 and 8 is lighting quick. You’re grabbing two back-to-back downshifts – bam, bam – and then muscling the bike from right to left as fast as possible. This is an area that should expose any flaws in tire profile. If the tire was too round the bike would be sluggish, requiring loads of effort to get turned and if it was too triangulated it would be unpredictable and want to fall into the corner too quickly. Thankfully front tire profile has never been an issue with newer generation Pirellis, as they have always given a great balance of quick turn-in and stability. And the DRC is no exception. It’s predictable with a very solid and planted feeling all the way across the tire’s profile while also allowing easy maneuverability.
Braking was another area the front tire shined, as the added sidewall stability of the ‘H’-shaped bead reduces flex when hard on the binders, further reducing the slight ‘mush’ that some of Pirelli’s race rubber is known for. This added stiffness was felt out back as well, as the rear tire was able to handle much higher acceleration loads before feeling it deform and potentially spin.
The one area that’s tough to comment on with a track-only test is the tire’s durability. I did put the new rubber through several 15-lap runs to see if the street-bred rubber would fade at high heat, and it passed with flying colors. Though you
Pirelli’s Diablo Rosso Corsa front tire profile is very neutral, allowing for both easy turn-in as well as ample stability.
also have to remember ambient and track temperature were quite cold that day so getting the tire extremely hot wasn’t easy. But what’s really impossible is getting a read on how they will last when exposed to thousands of street miles. Our day at the track showed very little wear but the true test will come once we can get our hands on a set to fit to one of our long-term units for a complete evaluation. Stay tuned for that down the road.
From wet to dry and cold to hot, Pirelli’s Diablo Rosso Corsa took everything Mother Nature or any of today’s sportbike could throw its way. The DRC astounded us with its outright grip as well as the feel and feedback it provided in a wide variety of conditions. Corner-exit drivability is far superior to the old tire and the front’s profile and construction remains one of our personal favorites. Without question several tire manufactures have recently elevated their game to match the remarkable performance of the latest generation of sportbikes and Pirelli is one of them. Assen proved