Thanks to the relatively large...
Thanks to the relatively large naked shoulder of the Diablo Rosso II, dry grip at full lean is exceptional, even on an insanely quick literbike such as the BMW S 1000 RR.
Over the past few years, motorcycle technology has progressed almost tenfold. Today’s literbikes come with more horsepower and electronics than most anyone will ever be able to comfortably — or at least legally — employ and even the latest naked bikes are leaps and bounds from yesteryear’s nakeds, with more horsepower and rider aids than ever before. Almost unnoticed though is the progress that has been made in tire technology by companies such as Pirelli, which has focused a great deal of its energy of late on building tires that can keep up with these rapidly evolving motorcycles. Proof of Pirelli’s efforts: the all-new Diablo Rosso II sport tire.
As was the case with the Diablo Rosso — the Rosso II’s predecessor, introduced back in 2008 — the goal with the Rosso II was to create a tire that would offer not only better mileage, but also better grip at maximum lean, better handling characteristics in wet conditions and increased braking performance. Improving on a tire that already worked well wouldn’t be easy, but by developing a new tread design, altering the tire structure and enlisting a completely new compound, Pirelli engineers have done just that.
The compound of both the Rosso II front and rear tires is completely new. The most notable change is to the rear tire though, which now features a Tri-Zone, Bi-Compound construction; the center compound (which makes up 75 percent of the tire) features a higher concentration of silica, a chemical compound known to add wet grip. And while additional silica would generally adversely affect a tire’s performance in warmer conditions, the new silica utilized by the Rosso II compound bonds better with the polymers — which are new in their own right — to ease that concern.
In contrast, the extreme shoulders (12.5 percent on each side) of the Rosso II are constructed from a fine carbon black matrix compound and are said to offer increased grip at maximum lean. The Rosso II front tire remains a single compound.
On the street, the Diablo...
On the street, the Diablo Rosso II provides great stability and great braking performance.
The tread pattern of the Rosso II may look similar, but looks can be deceiving. Taking what they learned from developing the Diablo Rosso Corsa — the recently released, more track-day oriented tire — Pirelli engineers lowered the land/sea ratio (amount of tread) on the Rosso II. Compared to the Diablo Rosso front tire, which had 12.4 percent of tread, the Rosso II front features just 10.5 percent of tread. In similar fashion, the Rosso II rear tire features just eight percent of tread, in contrast to the Diablo Rosso’s nine percent.
Generally speaking, reducing the amount of tread grooves in a tire will result in enhanced grip and feel, but reduced wet weather performance, as those grooves are what dissipate the water. By changing the shape and inclination of the grooves however, Pirelli engineers were able to give the Rosso II equal — if not better — water dissipation qualities. Also important to note is that the Rosso II’s contact patch has been enhanced, thanks not only to the new tread pattern, but also to the profile of the tire and new carcass structure.
A recent trip to Tooele, Utah, during the World Superbike weekend offered us the chance to put the new rubber through the ringer, and thanks to Mother Nature’s onslaught on the surrounding area during the event, we even got a chance to test the new Rosso IIs in wet and dry conditions — perfect, especially considering Pirelli’s emphasis on the tire’s wet-weather traction capabilities.
In the wet we made things especially interesting by mounting a Rosso II-shod Aprilia RSV4. What better way to test grip than on a 150-plus-horsepower literbike? While the pace stayed mellow on the dampened ride, we did notice an exceptional amount of grip — even when we were abrupt with the throaty Aprilia’s throttle as we tried to uncover any weaknesses in the tire.
The Bi-Compound Diablo Rosso...
The Bi-Compound Diablo Rosso II rear features a redesigned tread pattern with a lower land/sea ratio, but boasts equal water dissipation qualities. Wet weather performance was further increased by using more silica in the center compound. Note also the central rib, which was nonexistent on the Diablo Rosso.
When the skies cleared, we had an opportunity to test the Rosso IIs in a brief ride through some of Salt Lake City’s mountainous regions, where we would get a better feel for the tire’s handling characteristics in the dry. Although tight sections of road seemed equally as hard to find as a needle in a haystack, we did notice the Rosso II to be very stable on our high speed passes down an elongated, narrow stretch of road. And while limited to making a few quick passes up and down a mountain road, we also noted that braking performance is strong with this new Pirelli rubber.
Even on Miller Motorsports Park’s extremely quick outer course — where it was admittedly slightly out of its element — the Rosso II performed exceptionally well. Most notable is the fact that at speed, the tire is very communicative, almost telegraphing what the bike is doing underneath you. Also worthy of note is the fact that — off the brakes — turn-in with the Rosso II is quick, as are transitions. This was especially evident as we rolled through Miller Motorsports Park’s tricky Attitudes section.
One characteristic of the Rosso II that isn’t as welcomed is its tendency to squirm just slightly as the bike goes to maximum lean, a characteristic likely attributed to the transition between the center and shoulder compounds. Once you have made the transition to full lean however, you can employ the tire’s more expansive naked shoulder, which provides slick-like grip. Also noticeable when pushed is the tire’s tendency to make the bike steer rather heavy when trail braking.
To its credit though, the Diablo Rosso II was not designed to be pushed for quick lap times on the track. It was designed to offer a stable feel and improved mileage. In fact, Pirelli claims that in comparison to the Rosso, mileage has been increased some 10 percent and that you can expect to get around 8000 miles from the front and anywhere from 5000 to 6000 from the rear — depending on bike and rider of course. Judging by the look of the tires after the numerous laps on the track and our Rosso II-shod CBR600RR test unit’s planted feel through Miller’s sweeping corners late into the day, we don’t see why you shouldn’t either.
All said the new Rosso II is a step in the right direction. While there was nothing wrong with the Diablo Rosso, the Rosso II is exactly what Pirelli needed to keep up with the ever-evolving sportbikes of the 21st century. The tire is stable, performs well in the wet, and as ridden, has exceptional wear characteristics.
The Pirelli Diablo Rosso II is already available in an array of sizes and can be personalized with labels from gettyre.com/stickers. Price for the common 120/70ZR-17 front is set at $167, while rears range from $196 to $260, based on size. SR