October 14, 2004
Luxury performance vehicles are packed with refinement and technology, all of which are linked together to provide an exceptional driving experience. A critical link in the chain are the tires, which as the only means of contact with the road are responsible for translating all of the driver's inputs and turning the vehicle's performance into action.
The luxury sports car with its comfortable cabin, capable suspension and powerful engine places a challenging set of requirements on its tires. Tires must simultaneously deliver responsive handling and reassuring levels of grip, while also providing acceptable ride qualities. These tires must live in the real world where they are just as likely to experience bumps in the road as be asked to handle a favorite off-ramp or stretch of twisty back road.
Targeting vehicles in the luxury sport market, Dunlop has developed the SP Sport Maxx, which combines engineered refinements with Dunlop's motorsports heritage. The SP Sport Maxx is the second Dunlop road tire to carry the "Max" moniker. First was the SP Sport 9000 Hydromax, designed to deliver maximum resistance to hydroplaning, appropriate levels of handling along with a refined ride. The newer SP Sport Maxx aims to improve all areas of performance over its predecessor, the SP9000. To get an understanding of how the Dunlop SP Sport Maxx performs, Tire Rack team conducted a Real World Road Ride and Performance Track Drive to compare the SP Sport Maxx with two other Max Performance Summer tires, Bridgestone's Potenza S-03 Pole Position and the Pirelli P Zero Rosso.
Our evaluation used 2003 BMW 330Ci coupes, with 225/45R17 tires mounted on 17x8.0" wheels, which is a common Plus Zero size upgrade from BMW's Original Equipment tire size (205/50R17 on 17x7.0" wheels). Also, our evaluation used new full tread depth tires.
We also included a fourth 2003 BMW 330Ci fitted with the Original Equipment 205/50R17 Continental ContiTouringContact CV95 Grand Touring All-Season tires mounted on factory 17x7.0" wheels. We have found it helpful to have an OE-equipped vehicle in the test, to evaluate how installing the other products impacts the vehicle's ride and handling characteristics.
The ContiTouringContact CH95 features some of Continental's most advanced all-season tire technology. The tread pattern features three wide center grooves for efficient water drainage and large, stable outer tread blocks. The tread pattern is also heavily siped for good traction in light snow. The CH95 is being selected as Original Equipment on many European cars like the Mercedes-Benz C- and E-class, Audi A4 and A6, and the BMW 3, 5 and 7 series.
As one of several Original Equipment tires fitted to our BMW 330Ci test vehicles, the ContiTouringContact CV95 demonstrated its Grand Touring roots during our road ride evaluation. As we expected, ride quality and noise comfort ratings both scored higher than the Max Performance tires in this test, while road handling was found to be noticeably less responsive than the other test tires.
On our dry handling track, the CV95 displayed a sporty feel. The overall handling balance was surprisingly neutral, with a hint of oversteer in the rapid transitions through the slalom and also around the high-speed sweeping curve on our track. But ultimately, the overall grip level of this Grand Touring All-Season tire was just not equal to that of the three Max Performance Summer tires in this test.
Under wet track conditions, the ContiTouringContact CV95 displayed light and responsive steering, without the terminal understeer of most Grand Touring All-Season tires. Under acceleration away from the tighter corners, modest wheelspin and the resulting oversteer was always present. But in the end, like nearly every All-Season tire, the wet grip of the CV95 was just not equal to the three summer-only Max Performance tires in this test.
The Potenza S-03 Pole Position is a Max Performance Summer tire that was developed to meet the needs of the drivers of high performance sports cars, coupes and sedans by bringing Bridgestone's F1 tire technology and design to the streets while blending dry and wet traction without abandoning comfort and wear. The Potenza S-03 Pole Position features Bridgestone's UNI-T AQ II Technology that uses advanced compound and construction features to enhance and preserve wet traction through the tire's life.
The tire's outwardly simple, directional tread design incorporates several complex elements in its design to enhance wet weather capability. Tread block shapes are optimized to slice through and direct water from under the contact patch into the tire's circumferential grooves, and Hydro Evacuation Surface (H.E.S.) design on appropriate tread elements helps keep the water moving efficiently to combat hydroplaning in deep water. The Potenza S-03 Pole Position also benefits from Bridgestone's UNI-T AQII (Ultimate Network of Intelligent Technology Advanced Quality - second generation) and Super Extended Performance Optimization (Super EPO) tread compounds, which help reduce the effect of aging on a tire's wet grip. Two layers of special tread compounds are molded together, allowing the second, higher wet grip layer to be exposed in the tire's continuous center rib when new, and gradually becoming exposed across the majority of the tire's tread surface as the tire wears. This unique design helps reduce the impact of aging and reduced tread depth on the tire's ability to grip the road surface in the wet.
Out on the road, the Potenza S-03 Pole Position offered appropriate levels of ride quality and handling. Our team liked the responsive handling and crisp steering feel of this tire. But being the oldest design of the three Max Performance tires in this test, the S-03's ride and noise characteristics felt somewhat less refined than the others. While not objectionable, tread noise was a bit louder and the pitches more distinct than the other Max Performance tires. Expansion joints and sharper bumps in the road were more apparent when riding on this tire versus the others.
The Potenza S-03 Pole Position performed well on our test track in dry conditions. Inputs to the steering wheel yielded quick response, with just a hint of understeer in the tighter corners. Threshold braking felt surefooted, slowing the car rapidly. Average overall lap time was less than 0.1 second behind the first-place SP Sport Maxx.
In wet conditions, the S-03 Pole Position struggled to keep pace with the other two Max Performance tires in this test. Initial steering response was good, but the overall grip level was lower than the Dunlop or Pirelli tires, ultimately resulting in modest understeer. Accelerating through the side-to-side transitions of the slalom produced some power-on oversteer as the rear would begin to break loose. Our evaluation used new tires, so we were not able to evaluate the impact of Bridgestone's UNI-T AQII technology on a worn tire's wet weather performance.
The demanding German DTM series is considered to be the pinnacle of Touring Car Racing. Beginning with the 2004 season, the race tires for the DTM cars proudly wear the "SP Sport Maxx" name on their flanks to identify their close relationship to Dunlop's Max Performance Summer street tires developed for sports cars, coupes and sedans.
On the outside, SP Sport Maxx tires feature Dunlop's Integral Rubber Matrix tread compound molded into a multi-radius directional tread that features large, independent shoulder blocks, twin Hydro-Paddle intermediate ribs and a stable continuous center rib. These features work together to keep more of the tire on more of the road more of the time, provide turbulence-free water drainage and maintain constant road contact to impart more responsive handling, wet driving control and high-speed stability.
On the inside, SP Sport Maxx tires feature twin steel belts reinforced by Dunlop's Jointless Band (JLB) spiral-wrapped nylon to provide high-speed durability while minimizing weight. The tires feature a rayon cord casing for high-speed capability and ride quality.
During the road ride portion of our evaluation, the Dunlop SP Sport Maxx provided a good blend of sporty handling along with appropriate ride and noise comfort. The SP Sport Maxx seemed to envelope the bumps and those annoying little impacts better than the other two Max Performance tires tested, but did produce more booming noise with each impact. Tread noise levels were found to be appropriate for the category. Road handling scored well, with steering inputs feeling responsive and connected.
The SP Sport Maxx felt at home on our dry handling course. Steering response was very linear, with each change in steering input resulting in an equal change in turning force. There was no significant over- or understeer, providing balanced overall handling and producing the fastest average overall lap time of the test.
In wet conditions on the test track, the SP Sport Maxx also performed well. As in the dry, overall handling balance was good, without the terminal understeer or snap oversteer often found in the wet. The Sport Maxx achieved the highest lateral g's, which aided driver confidence, and easily set the fastest average overall lap time in this test.
Italians have always identified the color red with passion, Pirelli's P Zero Rosso (Rosso, ro' so, Italian for red) aims at fulfilling a passion for driving. Tire design techniques, raw materials and manufacturing methods have been combined in the P Zero Rosso to produce Pirelli's most comfortable Max Performance tire. The P Zero Rosso System includes both asymmetric and directional tread designs, each tuned to satisfy the unique performance needs of different types of vehicles and use. The directional version is available in very limited sizes, each designed for use with a specific Original Equipment fitment. Our evaluation used the asymmetric version which is more widely available, and suitable for nearly all applications.
The Asimmetrico tread pattern combines a semi-slick center rib (which enhances driving precision while accelerating and braking) with robust outer shoulder and intermediate tread blocks which are connected by circumferential "multi-ring" ribs (to enhance dry grip) and independent blocks of the inner intermediate rib and shoulder which are separated by wide grooves (to help eject water). Considerable use has been made of curved grooves, which help complement the circumferential grooves to reduce noise and resist hydroplaning. The P Zero Rosso used a silica-enhanced tread compound to provide better grip in the wet and lower rolling resistance in the dry. The tread is supported by PenTec cord (originally developed by Allied Signal for space exploration) which is used to reinforce lightweight steel belts to give more high speed stability while reducing tire weight and flatspotting when parked overnight. Single-wire beads are carefully wound into a "diamond" shape to provide a uniform distribution of tension from the wheel to the tire as the vehicle drives, resulting in a comfortable tire that performs.
Out on the road, the P Zero Rosso delivered ride and handling qualities appropriate for a Max Performance Summer tire. Our team found the ride just a bit firm over the sharp expansion joints on the concrete expressway, but without the usual booming sound normally associated with sharp impacts. Tread noise across a variety of concrete and asphalt surfaces was also found to be the lowest of the three Max Performance tires in this evaluation. Overall handling was appropriate for the category, but rated just behind the other two Max Performance tires. Steering inputs felt very responsive and willing to turn off of center, but were almost nervous when driving across rutted or grooved surfaces.
On the dry handling course, the P Zero Rosso performed well. Subjectively, the P Zero Rosso did not feel as fast as it actually was. This tire felt a little "edgy" when reaching for the limit of traction, where it was sometimes hard to judge just where the limit was. This didn't prove to hurt overall performance too much, as the average overall lap time was nearly identical to the first-place Dunlop SP Sport Maxx.
In the wet, the P Zero Rosso displayed appropriate levels of traction and responsiveness. The overall grip level was good, but not quite able to match the level of the Dunlop SP Sport Maxx. Steering felt responsive, with a hint of understeer, most noticeably around the skid pad portion of our course.
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