Front
Dunlop introduces the new Qualifier, the ultimate sport bike tire
Dunlop Motorcycle Tires is renowned for its ability to bring racing tire technology to the street. With the introduction of the all-new Qualifier (or Q), a DOT-spec sport bike tire that brings racetrack-level performance to the street, Dunlop ushers in a whole new era of ultra-high radial sport tire performance for serious riders.
In determining the criteria for the Qualifier-the successor to the street-going D208ZR-Dunlop's development team faced a daunting task: elevate all aspects of performance while maintaining the consistent, predictable and sure-footed all-weather handling of the phenomenal D208ZR, the best-selling sport bike tire in the U.S.
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THE GOAL
"What we set out to do was build a street tire out of a race tire," said Dunlop's Motorcycle Product Development Manager, Mick Jackson. "We had the D208GP legacy to tap into as well as our all-new Sportmax GP, so our goal was to preserve as much race tire performance as possible while engineering the new tire to meet the stability, durability and wet-weather performance standards inherent in the D208ZR.
COMPOUNDS & PROFILES
"From this point we used FEA (finite element analysis) to determine the optimum profiles and compounds," said Jackson. "The rear tire retains the profile of the D208ZR but the compounding is now very similar to the medium-traction material found in our new Sportmax GP race tire. The compound is a blend of three polymers reinforced with a high-surface-area carbon black and a proprietary resin to maximize wet and dry grip and durability. For the front tire profile, we worked very closely with our UK race tire group. The front profile follows the aspect ratio of the Sportmax GP, while its compound is quite close to our D208GP tire." The more triangulated profile of the front tire promotes quicker turn-in and lighter steering, and also contributes to a larger footprint at maximum lean angles.
Compound and profile selection for the Q went hand-in-hand with tread pattern development, jointly spearheaded by SRI (Sumitomo Rubber) in Japan and Jackson's team in Buffalo, New York. "With our latest compounds, we were able to significantly increase the amount of land area in the tread pattern while maintaining the wet weather performance of the 208ZR," said Jackson. The ratios of smooth tread to grooved tread (land/sea ratio) on the final design bear this out. On the Qualifier front, the amount of land area has increased 6.0 percent (to 93.1 percent) while the Qualifier's rear land area is 92.8 percent, an increase of 3.4 percent compared to the 208ZR. Bottom line: Bigger footprints front and rear help increase grip at both ends.
CONSTRUCTION
The cut-angle breaker construction of the front tire utilizes two nylon carcass plies and two aramid reinforcing belts. As used on the D208GPA tire, Jointless Band (JLB) rear tire construction features a continuously wound tread belt to assure consistent tire diameter in all operating conditions. The 180/55ZR17 and 190/50ZR17 sizes utilize one nylon carcass ply and one aramid JLB belt.
The 200/50ZR17 has two nylon carcass plies and one aramid JLB belt. Improvements in belt design and construction have significantly reduced weight in the Qualifier rear tire by approximately one pound compared to the equivalent 208ZR sizes. This reduction in unsprung weight can profoundly reduce the gyroscopic impact of the tire/wheel combination and contribute to quicker acceleration and steering.
TREAD PATTERNS
The Qualifier's front and rear tread patterns remain very similar to the Sportmax GP design that rules the AMA's Supersport class. An extension of Dunlop's cosecant-curve design first introduced on the D207 and perfected on the D208GP, the tread grooves are designed to continuously coincide with the forces running through the tire. As the curving tread pattern travels across the tire to the shoulder area, it keeps the driving and braking forces aligned properly as cornering forces come into play. The tread pattern of the Q contains more longitudinal elements in the center of the tread for enhanced wet-surface grip, yet sacrifices none of the D208ZR's excellent dry-surface wear performance. It is visually distinguishable from the ZR tread pattern by the V-shaped chevrons molded into the tread grooves in the middle portion of the tread. Additionally, the front tire features tread elements which are staged at different intervals around the tire. This variable pitch pattern reduces frequency-generated noise and vibration.
OUT OF THE LAB AND INTO THE REAL WORLD
Dunlop is well known for its exhaustive evaluation process and this crucial aspect was significant in the final rendition of the new Qualifier. Dozens of possible profile, compound and tread-pattern combinations were narrowed to several dozen design variations that were then subjected to real-world riding and racing conditions.
"We did extensive testing at our facilities in Mireval, France, Almeria, Spain and our Huntsville, Alabama Proving Grounds in the U.S.," said Jackson. When the final design was evaluated against the D208ZR on a 600cc sport bike at Virginia International Raceway's (VIR) 1.65-mile South Course, the results were astounding: The Qualifier covered the course 3.5 seconds faster (1.13:796 vs 1.17:305) than the D208ZR.
Where does this increased performance manifest itself? Compared to the D208ZR, the Qualifier has improved side grip and better drive traction out of corners, allowing for higher cornering speeds and quicker exits. On the front, the Qualifier requires less steering effort, which means that directional changes-turn-in and transitions-occur more quickly.
At the VIR evaluation, data acquisition indicated the Qualifier front tire speed through turns one and two-consecutive right-handers following the front straight-was 3.5 mph faster than the D208ZR. In turn four, a left-hander at the entrance to the Spiral, the advantage grew to 4.3 mph. The most dramatic example occured in turn nine, a right-hand kink at the entrance to the Climbing Esses, where the speed differential was a whopping 8.3 mph.
BALANCING PERFORMANCE AND DURABILITY
One might think that the stickier Qualifier heats up faster, and it does-a benefit for street riding-yet Dunlop's compound chefs have cooked up a formula that carries no more carcass heat than the D208ZR. That translates into tread life for the Qualifier that's equivalent to the D208ZR despite the Q's higher level of performance and predictable, confidence-inspiring handling.
The international effort to design the Dunlop Qualifier took 24 months from conception to product introduction, a measure of Dunlop's ability to marshal the strengths of its worldwide R&D capabilities and respond to market conditions. Another telling aspect of Dunlop's market reflexes is the fact that the Sportmax GP racing tire was just introduced to the world in February, 2005 and now, just eight months later, the company has introduced its street-going equivalent in the Qualifier.
The Qualifier will be available in the U.S. in January 2006 and will be offered in these sizes: front 120/60ZR17, 120/70ZR17, 130/70R16, rear 160/60R17, 170/60R17, 180/55ZR17, 190/50ZR17, 200/50ZR17.
In addition to Motorcycle Product Development Manager Mick Jackson, two engineers factored significantly in the development of the Dunlop Qualifier: Chris Zawistowski, Tire Development Engineer; Werner Brehm, Materials Engineer. In addition to this engineering team, Dunlop would like to recognise the Huntsville Proving Grounds team of Danny Roberts, Rich Conicelli and Levon Pendergrass for their tireless efforts in developing the all-new Qualifier.