Progress on the racetrack is easy to measure: Stopwatches don’t lie. In 2013 at Road America, back-to-back testing of the existing Dunlop Sportmax® D211™ GP-A race tire and the prototype GP-A Pro saw Yamaha riders Garrett Gerloff and Cameron Beaubier drop their lap times significantly on their R6 Daytona SportBikes.
“The new tire offers better edge grip,” said Beaubier. “I feel much more confident at full lean, and the bike seems to finish corners better and track better under braking.” Higher traction and better steering—it’s no coincidence the same compound and construction used in that prototype tire ended up in the production Sportmax GP-A Pro.
Introduced to the AMA Paddock at the 2014 Mid-Ohio round of the AMA Road Racing championship, the all-new DOT GPA-Pro is a step up in performance—and not just for professional riders. Dunlop’s Bi-Directional Technology and symmetrical tread pattern allow the new GPA-Pro rear to be flipped in rotational direction to get more laps out of the tire. This versatility helps club racers and track-day riders stretch their tire budget, especially at racetracks that are harder on one side of the tire than the other. Better grip and more mileage—the GPA-Pro benefits riders of all levels.
The GP-A Pro also features many innovative tire construction technologies developed by Dunlop in recent years, including:
+ Carbon Fiber Technology (CFT)
+ Jointless Tread application
+ N-TEC radial tire construction
+ Continuously wound Jointless Band (JLB) aramid-fiber belt
+ Continuously wound hex-beads
+ Intuitive Response Profile™ (IRP)
Carbon Fiber Technology
The GP-A Pro sidewalls (front and rear) incorporate the same carbon-fiber technology introduced in Dunlop’s Sportmax Q3. This carbon fiber reinforcement element in the sidewalls helps provide exceptional cornering stability and predictable and smooth transitional-steering traits.
Jointless Tread Application
The Jointless Tread application is key to the GP-A Pro bi-directional construction in the rear tire. Using the process pioneered on the bi-directional KR451 slick race tire, sophisticated production machinery in Dunlop’s Buffalo, New York plant winds the tire tread onto the carcass in a continuous strip allowing the rear tire to be run in both directions.
Symmetrical Tread Pattern
The GP-A Pro incorporates a new, symmetrical tread pattern on both front and rear tires, which was developed through real-world race testing at tracks around the country and the Dunlop Proving Grounds in Huntsville, Alabama. Compared to the previous-generation D211 GP-A, the “land-to-sea” ratio of the GP-A Pro tread pattern places appreciably more rubber down in the working area of the tires to offer enhanced performance.
Intuitive Response Profile
This rear-tire technology incorporates steep sidewalls for a unique tire profile that helps enhance steering response, feedback to the rider and overall cornering stability. Intuitive Response Profile (IRP) offers greater latitude in line choice while cornering and offers amazingly linear steering at various lean angles.
Beneath the tread, the carcass incorporates many of Dunlop’s high-tech advancements including hybrid N-TEC construction. N-TEC combines the benefits of compliant cut-breaker construction with stiffer, continuously wound aramid-fiber Jointless Band construction, and was first designed specifically for racing applications.
Continuous Wound Hex Beads
Like the Q3 and D211 GP-A, the GP-A Pro also features Dunlop’s continuously wound hex beads. This hex bead offers enhanced feel as the tire nears its cornering limits. They are also light and strong, which offers a benefit to steering response and cornering stability.
The Dunlop Advantage
Dunlop’s commitment to advancing the state-of-the-art in road race tires never ceases. As the exclusive spec tire provider in AMA Pro Racing since 2009, Dunlop can access the best riders in the country to inspire continuous tire development. The new machinery and manufacturing capabilities added to Dunlop’s Buffalo, New York manufacturing plant—the only motorcycle tire plant in the U.S.—gives Dunlop the capacity and flexibility to develop and manufacture new tire technologies. The Dunlop Proving Grounds in Huntsville, Alabama—the only motorcycle-only tire testing facility in the U.S.—gives Dunlop dedicated development advantages in various conditions. This combination—a close working relationship with top road racers, a high-tech manufacturing plant and a dedicated proving grounds—add up to a unique development advantage that created the revolutionary Sportmax GP-A Pro.
The Sportmax GPA-Pro is available from Race Tire Services, http://dunlopracing.com, (800) 772-8473.
Dunlop is the largest supplier of original equipment and replacement motorcycle tires in the U.S. and the only manufacturer of motorcycle tires in North America. With North American operations located in Buffalo, NY, Dunlop has been making and selling high-quality tires in the U.S. since 1923. For more information, visit www.dunlopmotorcycle.com