Vehicles used:
2008 BMW E90 325i Coupe

In the fall of 2007, Dunlop brought the successful Direzza Sport Z1 to North America. Already successful in Asia for drifting & time attack track events, the "Zed One" quickly found many fans among enthusiasts in North America driving potent performance vehicles on the street or in track & autocross events thanks to its blend of excellent dry traction, respectable wet grip & reasonable road manners. Not resting on its own success, Dunlop has taken the Direzza Sport Z1 another step forward with the new Star Spec version. Designated with a simple 5-pointed star on the sidewall (not to be confused with the symbol used to designate BMW Original Equipment status), the Direzza Sport Z1 Star Spec features a revised tread compound on top of the original tire's architecture aimed at improving initial dry grip during the first lap of track driving or in autocross competition runs when tread compound temperatures are at less than maximum levels. Dunlop's own testing has also shown that wet traction is improved due to the lower operating temperatures found in these conditions (versus in the dry) puts the tire in the sweet spot for enhanced traction provided by the new tread compound.

To find out how the revisions of the Dunlop Direzza Sport Z1 Star Spec impact road manners & enhance track performance, the Tire Rack team conducted a Real World Road Ride & Performance Track Drive comparing it to several favorites in the Extreme Performance Summer tire category, the Bridgestone Potenza RE-01R, Hankook Ventus R-S2 Z212 & Yokohama ADVAN Neova AD07. Our evaluation used 2008 BMW 325i E90 coupes with new, full tread depth 225/45R17 tires mounted on 17x8.0" wheels.

What We Learned on the Road

Our 5.6-mile loop of expressway, state highway & county roads provides a great variety of road conditions that include city & highway speeds, smooth & coarse concrete, as well as new & patched asphalt. This route allows our team to experience noise comfort, ride quality & everyday h&ling, just as you would during your drive to school or work.

All four tires were praised for their responsive h&ling & agile feel thanks to the crisp steering response & stable cornering that are hallmarks of the Extreme Performance Summer tire category. Of particular note was the Yokohama ADVAN Neova AD07, which continued to live up to its reputation for laser-sharp steering response. Nearly matching the quick steering feel of the Yokohama was the Dunlop Direzza Sport Z1 Star Spec. The "Zed One Star Spec" displayed a linear, connected feel in the steering wheel. The Bridgestone Potenza RE-01R followed in its rating for overall road h&ling with somewhat slower steering response than the Yokohama or Dunlop. Rounding out the group was the Hankook Ventus R-S2 Z212 with levels of h&ling & steering response that were appropriate for the Extreme Performance Summer tire category but not quite equal to the other tires in this test.

Some tread noise is a normal by-product of the large tread block elements that are a common feature of Extreme Performance Summer tires. Among the tires in this test, the Potenza RE-01R produced the least amount of tread noise of the group. The Direzza Sport Z1 Star Spec also did a good job minimizing tread pattern noise with only modest noise across the variety of surfaces on our test route. The ADVAN Neova AD07 & its large tread block elements generated several distinct pitches on asphalt surfaces at higher speeds, while the Ventus R-S2 Z212 produced noticeable tread noise on all road surfaces.

Maximizing ride comfort is not normally a high priority for the tire designers when they develop Extreme Performance Summer tires. & while you won't confuse the Bridgestone Potenza RE-01R with a comfort-oriented touring tire, it did provide the best ride quality of the tires in this test. The Dunlop Direzza Sport Z1 Star Spec was also praised for its ride quality, doing a good job minimizing the harshness of small- to medium-sized impacts. The Yokohama ADVAN Neova AD07 felt firm when driving over the smaller bumps & expansion joints along the route & bordered on harsh when encountering the bigger impacts. The Hankook Ventus R-S2 Z212 was also found to be somewhat harsh over uneven surfaces & patched sections of the route, feeling less refined than the other three tires tested.

What We Learned on the Test Track

Our 1/3-mile per lap test track course includes 90-degree street corners, lane changes & simulated expressway ramps. Run in both dry & wet conditions, the test track allows our team to experience the traction, responsiveness, h&ling & drivability normally only encountered during abrupt emergency avoidance maneuvers or competition events.

Extreme Performance Summer tires are designed to deliver sporty road h&ling & on-track performance & this group didn't disappoint during our dry track test. Our test format normally sees tires build significant tread temperature during driving with brief pauses between drivers while a different product is driven on the track. & while the revised tread compound of the Dunlop Direzza Sport Z1 Star Spec is designed to enhance dry grip at lower tread temperatures, it also proved to aid dry grip under our test conditions & post the quickest overall lap time of the test. The Z1 Star Spec felt responsive & nimble as it was quickest through the lane-change slalom section of the course. Yokohama's ADVAN Neova AD07 was able to generate significant levels of lateral grip around the skidpad section of the course but couldn't quite match the overall poise & balance of the Dunlop. The Bridgestone Potenza RE-01R was able to lap the course within 0.34 seconds of the first-place Dunlop thanks to its forgiving nature & easy-to-drive fast feel when driven at the h&ling limit. The Hankook Ventus R-S2 Z212 rounded out the group, feeling responsive but just not quite up to the performance level of the other three Extreme Performance Summer tires in this test.

Traditionally, wet traction has been one of the largest sacrifices to achieve the significant level of dry grip found in Extreme Performance Summer tires. But several of the tires in this test show the advances being made in tire design with respectable wet traction in addition to their dry performance. In the wet, the Direzza Sport Z1 Star Spec was the clear favorite among our team, sweeping the test for best lane change slalom sector time, highest lateral g-forces & fastest overall lap time. This tire displayed excellent overall balance, which translated to driver confidence & quick lap times. The Potenza RE-01R was second quickest around the course with somewhat less grip & responsiveness than the Dunlop. The ADVAN Neova AD07 followed, feeling a bit more skittish & less predictable in transitions & around the 90-degree corners. The Ventus R-S2 Z212 was a distant 2.1 seconds behind the first-place Dunlop, feeling very nervous & unstable in all areas of the course.

Product Details

Bridgestone Potenza RE-01R (Extreme Performance Summer): The Potenza RE-01R (with the "R" signifying "Revolutionary") is the Extreme Performance Summer tire member of Bridgestone's global family of Potenza performance tires developed for enthusiastic sports car, sports coupe & performance sedan drivers. The Potenza RE-01R is designed to provide high levels of traction, responsive h&ling & driving control in dry & wet road conditions. The Potenza RE-01R is not intended to be driven in near-freezing temperatures, through snow or on ice. The Potenza RE-01R molds a soft tread compound featuring a superior wear resistance polymer to improve both wet & dry grip while contributing to wear & durability.

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 & performance sedan enthusiasts looking for race tire-like traction on the street or for use in autocross, drifting & 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.

As an evolution of the Direzza Sport Z1 & continuing to use the same tread design, the Direzza Sport Z1 Star Spec tread compound helps provide faster lap times from the start by developing more traction in temperate temperatures along with consistent grip on subsequent laps when the tires are fully warmed up.

Hankook Ventus R-S2 Z212 (Extreme Performance Summer): The Ventus R-S2 Z212 is Hankook's Extreme Performance Summer tire developed for the drivers of sports cars, sporty coupes & high performance sedans. The Ventus R-S2 Z212 is designed to provide crisp cornering, responsive steering & a firm grip. Like all summer tires, the Ventus R-S2 Z212 is not intended to be driven in near-freezing temperatures, through snow or on ice.

Yokohama ADVAN Neova AD07 (Extreme Performance Summer): The ADVAN Neova AD07 is the Extreme Performance Summer tire member of Yokohama's global family of ADVAN performance tires developed for sports car, sports coupe & performance sedan enthusiasts who love sport driving. Used as Original Equipment on the Lotus Elise, the ADVAN Neova AD07 is designed to provide high levels of traction, responsive h&ling & driving control in dry & wet road conditions. The ADVAN Neova AD07 is not intended to be driven in cold temperatures or in snow.