Grassroots Motorsports
Issue link: http://grassrootsmotorsports.epubxp.com/i/501675
Grassroots Motorsports 124 Here's a tire with an interesting history. The brand is owned by Sumitomo in Asia, but the American distribution rights land in Goodyear's portfolio. As such, new models and versions typically debut in the home market frst, then hit shelves in the U.S. in a tweaked form and select sizes one year later. Gearheads armed with Google Translate can usually know what to expect based on the info posted overseas, and Dunlop seems keen on frequent tweaks to stay near the top: The Z1, Z1 Star Spec, ZII and now ZII Star Spec have all arrived a year or so apart. The line is known for super-responsive handling, small slip angles and somewhat abrupt breakaway characteristics. These properties reward the fnesse driver who likes a willing dance partner, but punish those who like to throw a car around. The Star Spec version of the ZII seems to have softened the blow a little on overdriving, a l l o w i n g f o r m o r e room to maneuver. It's especially good at what industry experts call compound loading. This has nothing to do with tread compound and everything to do with multitasking at the in-between edges of the fric- tion circle–where the tire is supporting large lateral and longitudinal loads. The Toyo R1R is another tire that does this extremely well, and the ZII is moving in that direction. Along the way, however, the ZII Star Spec has also picked up some heat intolerance. We frst saw it on the skidpad, where times increased along with the lap count. Judicious use of the water sprayer was required to get times back in line. Still, we could never rep- licate those three fast skidpad laps we nailed in the very frst 30 seconds of use. Instead, after spraying, we'd get one quick lap and two a touch slower. And even those frst three fyers were only good enough to rank second to last in steady-state grip. Respon- sive on-course action is this tire's forte. Once they took to the test course, both drivers fell in love with the dynamics of this tire. It was a great partner in crime, seem- ingly directly connected to their inputs with no delay. Its slalom control was the best of the bunch–not just with turn-in response, but predictable turn-back, meaning speed could easily be carried past the last cones in the slalom. Predictability and stability in the sweeper entries were also key to quick lap times. By the end, the Star Spec was the darling of the pre- 2015-generation tires, well beyond the Rival and AD08R in times. UNAVAILABLE FOR DUTY Notable absentees from our testing are the 2014 version of the Hankook RS3 (V2), which has been stuck in its yearly backorder conundrum for months. A dock- worker strike at the port in Cali- fornia has extended the timeline. In a similar vein, Toyo recently upgraded its R1R to a 200-tread- wear version, although they aren't specifying if the design has changed from the previous 140- marked tire. The new tires are currently only available in a few sizes, not yet including the 205 or Dunlop Direzza ZII Star Spec average run best run best lap expert driver: 48.5 48.3 24.0 guest driver: 49.5 49.3 24.5 (all times in seconds) FEATURE: STREET TIRE TEST