May 21, 2009
- - adjective
- Of a character or kind farthest removed from the ordinary or average.(dictionary.com)
Extreme Performance Summer tires are not ordinary by any standards. Designed to bring race tire-like performance to the street, today's Extreme Performance Summer tires are capable of delivering ultimate dry traction levels on par with yesterday's dedicated track tires. All this while still providing longer treadwear and more reasonable road manners than any track tire could ever deliver.
This year there is a bumper crop of new Extreme Performance Summer tires with new products from Bridgestone, Kumho and Yokohama. To find out how these new tires perform, the Tire Rack team conducted a Real World Road Ride and Performance Track Drive comparing the Bridgestone Potenza RE-11, Kumho Ecsta XS and Yokohama ADVAN Neova AD08 with the winner of our last Extreme Performance Summer tire test, the Dunlop Direzza Sport Z1 Star Spec. Our evaluation used 2008 BMW E92 328i coupes with new, full tread depth 225/45R17 tires mounted on 17x8.0" wheels.
Our 6.6-mile loop of expressway, state highway and county roads provides a great variety of road conditions that include city and highway speeds, smooth and coarse concrete, as well as new and patched asphalt. This route allows our team to experience noise comfort, ride quality and everyday handling, just as you would during your drive to school or work.
Our team found the entire group displayed excellent handling and nimble responsiveness, hallmarks of the Extreme Performance Summer category. The Yokohama ADVAN Neova AD08 delivered the most responsive steering of the group, reacting immediately to driver inputs. The Dunlop Direzza Sport Z1 Star Spec was right behind, also feeling crisp and responsive. Turning the steering wheel with the Bridgestone Potenza RE-11 tires required a little more effort, but gave a reassuring feel to the driver. The Kumho Ecsta XS was also well liked, but displayed a small dead spot on center then responded quickly as more steering input was put in by the driver.
The Potenza RE-11 showed a clear advantage over the other three tires in the test for overall ride quality, doing a surprisingly good job (for an Extreme Performance Summer tire) rounding over the sharper bumps and expansion joints along the route. The ride quality of the ADVAN Neova AD08 was 2nd best in the group, noticeably better than its predecessor the ADVAN Neova AD07. Our team did notice this tire produced lots of impact noise creating the impression that its ride was rougher than it actually was if you were to factor out the impact sound. The ride quality of the Direzza Sport Z1 Star Spec was found to be slightly firmer than the RE-11 and AD08 with modest harshness felt when driving over sharper impacts. The Ecsta XS proved to have ride comfort appropriate for the category, but was the firmest of the group.
All four tires in this test did produce noticeable tread pattern noise volume and none would be confused for the quiet ride of a touring tire. But the Potenza RE-11 and ADVAN Neova AD08 both did a good job hiding their tread noise levels by generating a broad, white noise that often disappeared into the background of surrounding traffic and wind noise as speeds increased. The Direzza Sport Z1 Star Spec and Ecsta XS tires both produced several distinct tones or growls at certain speeds making their tread noise more apparent than the others.
Our 1/3-mile per lap test track course includes 90-degree street corners, lane changes and simulated expressway ramps. Run in both dry and wet conditions, the test track allows our team to experience the traction, responsiveness, handling and drivability normally only encountered during abrupt emergency avoidance maneuvers or competition events.
Our team always looks forward to testing Extreme Performance Summer tires under dry track conditions and this group did not disappoint. The Yokohama ADVAN Neova AD08's steering response was quick and precise, braking was sure-footed and overall handling felt well-balanced which combined to help this tire deliver the fastest overall lap time of the test. The Dunlop Direzza Sport Z1 Star Spec was close behind, also aided by responsive handling and excellent traction during transitions, cornering and braking. The Kumho Ecsta XS provided exceptional ultimate grip around our skidpad breaking the 1.0g barrier for the first time in our product test history. What this tire gained in ultimate grip was given back in a lack of precision, however, as vehicle transitions felt somewhat less in phase with driver inputs than the others, making it harder to maximize the tire's performance during rapid transitions. Rounding out the group just 2/10ths second behind the first place Yokohama was the Bridgestone Potenza RE-11. This tire proved to be a favorite for many of our team thanks to its confidence-inspiring handling that allowed drivers of varied skill levels to comfortably explore the limits and maximize tire performance.
Things were just as close in the wet, too, with the Potenza RE-11 edging out the others by the slimmest of margins. In addition to the fastest lap time, the RE-11 was able to generate the highest average g forces and the fastest slalom segment time of this test thanks to its high level of wet grip and predictable handling. The steering response and overall handling of the Direzza Sport Z1 Star Spec felt comfortably in harmony, providing driver confidence and quick lap times. The quick steering response of the ADVAN Neova AD08 in the dry made this tire feel a little nervous and edgy in the wet requiring smooth inputs. In the end, the Direzza Sport Z1 Star Spec and ADVAN Neova AD08 lapped our track with identical average times despite the noticeable difference in subjective feel. Rounding out the group was the Ecsta XS which displayed noticeably less overall wet traction than the other three tires. The lack of precision felt in the dry carried over more noticeably to the wet making this tire a bit hard to control at the limit.
Bridgestone Potenza RE-11 (Extreme Performance Summer): The Potenza RE-11 is an Extreme Performance Summer tire developed for enthusiastic sports car, sports coupe and performance sedan drivers. The Potenza RE-11 is designed to combine traction, handling and driving control with good noise and ride comfort. The Potenza RE-11 is tuned for dry and wet conditions, but like all summer tires is not intended to be driven in near-freezing temperatures, through snow or on ice. Read more.
Dunlop Direzza Sport Z1 Star Spec (Extreme Performance Summer): The Direzza Sport Z1 Star Spec is Dunlop's Extreme Performance Summer tire developed for serious sports car, sports coupe and performance sedan enthusiasts looking for race tire-like traction on the street or for use in autocross, drifting and track events. The Direzza Sport Z1 Star Spec is for drivers who don't want to wait as long for their tires to come in during initial runs, as well as drivers of lighter weight vehicles who are often confronted with the task of working tire temperatures up to the point of generating peak grip.
Kumho Ecsta XS (Extreme Performance Summer): The Ecsta XS (eXtreme Street) is Kumho's Extreme Performance Summer tire developed for passionate driving enthusiasts looking to make the most of their vehicle's capabilities in competition, at the track or on the street. The Ecsta XS is designed to deliver Kumho's ultimate level of dry road performance while maintaining wet traction. Like all summer tires, the Ecsta XS is not intended to be driven in near-freezing temperatures, through snow or on ice. Read more.
Yokohama ADVAN Neova AD08 (Extreme Performance Summer): The ADVAN Neova AD08 is Yokohama's Extreme Performance Summer tire developed for the drivers of sports cars, sports coupes and performance sedans that have a passion for sport driving. The ADVAN Neova AD08 is designed to provide high levels of traction, responsive handling and driving control on dry and wet roads, however it is not intended to be driven in near-freezing temperatures, through snow or on ice.
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