Mmm, donuts ... warm, sticky donuts. Dunlop's new Qualifier tires were introduced at Parump. image by kevin wing

Suppose you're a major motorcycle tire manufacturer, one that's accustomed to dominating in the race and consumer markets. Now, continue to suppose that your best selling sporting street tire has a reputation for being, well, less than stellar in some situations. What do you do? Sit back and say that, since it's selling extremely well, nothing really needs to change? Or do you acknowledge that the state of the sportbike art is a constantly moving target and throw your best engineers and riders at developing a new street tire? If you were Dunlop, what would you do?

Computer, Laboratory and Track Development

Just over two years ago, Dunlop gathered all of the current generation sportbikes and sticky street rubber in Pau, France for what Mike Manning, Dunlop Product and Marketing Manager, termed a "huge benchmarking exercise." The company was well aware that riders in the know, including the bulk of the motojournalist community, felt that the D208ZR was, despite its sales, lacking in a few key areas. So, the initial focus was to gather an accurate assessment of where the D208ZR stood in comparison to the competition. The next step was formulating a goal for the next generation tire.

The design goals for the Qualifier were threefold: improve grip, handling and acceleration. All proposed changes throughout the process had to be analyzed as to how they would affect these goals. To speed the development of the Qualifier, Dunlop's engineers utilized what could be called virtual tire testing in conjunction with the traditional bike and professional rider on prototype tires approach. Using a process called finite element analysis (FEA) and finite element modeling (FEM), engineers were able to replicate events on computers, creating rolling simulations to measure forces on the tire with enough accuracy to simulate how various constructions of tire will affect contact patch. These simulations run the gamut of situations that a street tire is likely to encounter, from a wide range of lean angles, wet conditions or contacting obstacles in the road.

In the past, developing a new tire would have primarily taken place on the track, but now, the combination of computer modeling and lab testing lessens the number of prototype constructions of tires from twenty or more to ten or twelve, according to Dunlop Motorcycle Development Manager Mick Jackson. Still, the high-tech approach doesn't end once the riders start giving their input on the tire performance. The test bikes used in development were outfitted with data acquisition equipment that recorded handlebar movement, suspension travel, dynamic front and rear tire temperature, even the frequency of chatter. The engineers used this data to quantify the feedback from the riders about how the bike and tires behaved. The testing took place internationally at Dunlop facilities and race tracks in France, Japan, Spain and the US with riders from several international branches of the company.

Dunlop did 'virtual' testing on the Qualifier tire; back to back it's a better tire than their D208ZR rubber. image by Kevin Wing

The result of this two year process is a front tire with a more triangular profile (for quicker turn-in) that almost matches Dunlop's Sportmax GP race tire while the rear retains the profile of the D208ZR. The front's rubber compound is very similar to the medium compound of the Sportmax GP while the rear's is a descendant of the D208GP race tire. Three new polymers formulate the new compounds. The resulting increase in surface area of the molecules for binding with carbon black. This new, stronger bond helps reinforce the rubber, allow it to come up to temperature quicker and give more consistent grip/wear characteristics. Despite the quicker heating, Dunlop claims that the carcass carries no more heat than the D208ZR and, thus, offers similar tread life. Revised grooves in the tread give larger portions of rubber on the pavement at all lean angles without compromising wet weather performance. Larger rubber footprint also helps to increase grip.

The front carcass is constructed of two nylon plies and two Aramid (think Kevlar without the licensing fee) belts that, like the profile, were taken primarily from the Sportmax GP. The rear uses D208GPA-like Jointless Band construction (Dunlop's name for zero-degree belt) of three aramid strands wound around the carcass to limit expansion at speed. Both tires feature dual rubber compounds, but probably not in the way that you think. The first compound is in the bead apex just above the tire's bead. By changing the thickness and shape of this stiff compound, the sidewall's compliance can vary with lean angle. The second compound is the tread itself. Dunlop was able to incorporate all of these features into the tires while still keeping them significantly lighter than the D208ZR for quicker steering and acceleration.

The Qualifier's grooves have maintained Dunlop's cosecant-curve design that was introduced with the D207. The swoosh shape of the sipes keeps the driving and braking forces aligned properly as cornering forces come into play, which translates into having those forces transmitted to the rubber, not into the void of the groove, decreasing wear on the tire. The tread in the Qualifier has more longitudinal elements in the center of the tread to assist in clearing water, while the overall tread pattern itself is varied in its placement on the tire to minimize vibration and noise as it interacts with the road.

A Party in Pahrump

What made the Qualifier introduction somewhat different from most other press intros I attend was the variety of bikes present. (At new bike launches, you will find a bunch of the same model motorcycles.) Since the Qualifier was designed to fit all the current generation sportbikes, Dunlop had gathered two Honda CBR600RRs and CBR1000RRs, two Kawasaki ZX-6Rs and a superstock-prepped ZX-10R, one Suzuki GSX-R750 and two GSX-R1000s, and Yamaha R6 and R1. With this wide range of motorcycles to sample, we'd have plenty of opportunities to experience the Qualifier's strengths and weaknesses. In a smart, though not terribly popular move, the first track sessions on these bikes were with the departing D208ZRs mounted. While we all understood the logic of doing a side-by-side comparison, events like this bring out the child-on-Christmas-morning in all of us.

The first sessions achieved Dunlop's goal. We were reminded that the D208 wasn't really a bad tire. However, it wasn't a great tire either. The primary marks against it were the front's rounded front profile and relatively heavy weight. Both of these conspired to make turn-in slower than it should be. The profile was also responsible for causing bikes to stand up when braking in a corner-not exactly the prescription for confidence when trail braking into a corner. Still, the D208 could rail through corners offering good grip all the way up to maximum lean. Once at maximum lean, the edge grip was not as confidence inspiring as I would have liked. Riders who are more aggressive on their throttle application at the corner exit than I also noted that the rear tire became greasy after just a few laps-even on the 600s.

On my first lap out with the Qualifier-before I'd even scrubbed in the tires-I was immediately able to notice a difference in the steering. Once I got up to speed, I was astounded with the change in the bike's steering and handling. Steering inputs were responded to with razor-sharp precision, and I began to alter my lines slightly to account for this new ability. When leaned all the way over on the Spring Mountain Motorsports Ranch track's two long sweepers (turns one and two), I was able to carry maximum lean much more comfortably. The bump at the exit of two that had made the rear D208ZR skittish on the power could be taken much more aggressively, effectively shortening the straight. The middle portion of the track features several side-to-side transitions which could be made with much less effort, thus translating into more speed. The higher velocity exits, coupled with the lighter weight of the Qualifier, meant that the bikes accelerated more quickly, too. On a couple of bikes, that change forced me to decide between carrying a gear up to the rev limit or banging an additional upshift before a brake point. With the D208, that never happened. So, later in the day, I had no trouble believing the telemetry Mick Jackson showed us of two laps on the same bike with the same rider just a few minutes apart with the only difference being the D208ZR versus the Qualifier. (An example of how big the change in the Qualifier made in lap times comes from Virginia International Raceway's 1.65-mile South Course where the rider recorded a best lap time that was 3.5 seconds faster than that of the D208ZR.)

While the front tire's more triangular profile made steering more responsive, where the profile's change really shone was when braking while leaned over. Whether I was trail braking into a corner or beginning to apply the brakes while already cranked over, the Qualifiers never exhibited the tendency to stand up that the D208ZRs did. This had an immediate effect on one of the sections of the track that had been most problematic for me with the D208s. On the Spring Mountain track, the only sizable straight feeds into a fast right-hand sweeper (turn 8) ending in another straight that is so short that it almost doesn't count. This straight then drops you off into a 90 degree left/right pair of turns (9 and 10, respectively). To make time through this section, you need to carry as much speed as possible through the sweeper, begin applying the brakes while still leaned over, stand the bike up to finish the braking before pitching it into the left-hander. With the D208ZRs, maintaining my chosen line required me to wrestle with the bike's tendency to stand up under braking, taking my attention away from the braking itself. Once the Qualifiers were mounted, the place that had required full attention just to maintain my line became one of my favorite sections of the track.

I spent much of the afternoon of the first track day playing with different lines in this section. As my confidence in the tires increased, so did my cornering speeds. Towards the end of the day, as I was taking a dual apex line through the sweeper, my plan was to clip the first apex and let the bike scrub off speed as it drifted wide. Only this time, I'd gotten into the corner hot enough that, as soon as the bike was leaned over, both tires began to slide taking me dangerously close to the edge of the track. Through no effort of my own (I was simply trying not to do anything stupid), the Qualifiers gathered themselves up and sent me back on my way-off line but still upright. The slide itself was benign with the front staying completely neutral and a slight chatter in the rear from the engine braking. After a full day in the saddle, I couldn't wait for the second one.

My plan for the two-day test was to spend the first day concentrating on the 600s then devoting the second to the 1000s. So, I began the second day on the Honda CBR1000RR. While the tires behaved the same, I had to juggle shift and brake points to account for the difference in weight and power of the big Honda. In my second session on the bike, I felt I'd come to grips with the bigger bike and started to up the pace.

If I were a better writer, I'd have come up with a clever way to weave the results of my final run into turns 8 and 9 throughout this article, reaching a comic crescendo that culminated in both myself and the bike sliding to a stop in the dirt on the outside of the track. Sorry, that's not in the cards. All I can say is that I exited the right-hand sweeper too hot, tried to cram too much braking into too little space, and attempted to force the bike into the left-even though I was way off line and still on the brakes—when I ran out of talent. Insert the sounds of grinding CBR1000RR plastic and the ear-ringing thwack of a brand new HJC helmet here.

The Qualifiers, as good as they are, can't rewrite the laws of physics.

As I spent the rest of the day icing my shoulder and watching the other kids play, I did my best to eavesdrop on conversations about how their experiences changed. The big news was that the Dunlop support crew lowered the air pressures from the street settings of 34 lbs. front and 36 lbs. rear to lower, more track oriented ones. The results were-—if my intel can be trusted—more feedback from the front approaching the limit and more than twice the number of hard laps before the rear tire got greasy when compared to the D208ZR.

Now that you're interested in the Qualifier, you'll have to cool your heels until January 2006 to sample a set of your own. Qualifiers will be available in the following sizes:

Front
120/60ZR17
120/70ZR17
130/70R16

Rear
160/60R17
170/60R17
180/55ZR17
190/50ZR17
200/50ZR17

If you follow the changes in tire technology like most sportbike riders, you owe it to yourself to sample a set of Qualifiers to see how they stack up to what you're running now. Since these street tires can handle the extended abuse of the race track—at street air pressures to boot—they should work pretty well in the situations they encounter on public roads.