Grassroots Motorsports
Issue link: http://grassrootsmotorsports.epubxp.com/i/501675
Grassroots Motorsports 123 Despite handily winning our previous test across several ses- sions–autocross on asphalt, autocross on concrete, and laps on the road course–later reports from the feld did not always agree with our results. Some Rival drivers had diffculty adjusting to the feel of the tire or matching it to their car's setup. Others found it worked great, but only at certain sites and tracks. It has found a loving home, though, among low-buck endur- ance racers and track day afcionados. They appreciate this tire's long tread life and ability to easily deliver lap after lap of consis- tently fast performance. In the cone-dodging world, it has been quite polarizing: Some drivers love it, others curse it. The last time we tested it, we loved this tire. However, upon mounting it on the tightly wound, well-balanced Miata, we started to appreciate the naysayers' perspective. And because it served as our control tire, we got plenty of time to examine it. On the skidpad, we could quickly fnd the Rival's limit and keep it there. The Rival delivered the same times between 28 and 36 psi–the largest spread of any tire tested this time. The Rival was also unaffected by the heat buildup of continual lapping. Unfortunately, progress has left this guy behind: It was the slowest of all in sustained steady-state grip. On the test course, both drivers struggled to make peace with this tire. They found it especially challenging to brake deep into the uphill sweeper after the fast run through the offsets. The Rival simply wanted to lock up. Similarly, our drivers felt uncertain on the downhill run out of the slalom and into the bottom sweeper thanks to the required multitasking. They also had diffculty putting down the power in the offsets, as the rear wanted to over-rotate and the slalom rebound after each turn-in was hard to predict. This unpredictability showed up in the results: Each driver struggled to put together two fast laps in a row. The single best lap times were consistent but also the slowest of the feld. BFGoodrich g-Force Rival average run best run best lap expert driver: 49.3 49.2 24.6 guest driver: 49.9 49.8 24.8 (all times in seconds) Yokohama Advan AD08R average run best run best lap expert driver: 49.5 49.0 24.3 guest driver: 50.0 49.7 24.7 (all times in seconds) The Advan AD08R is the latest in a long succession of products that began with the AD07. This is the tire that proved Yokohama was back in the game. On the skidpad, the AD08R appeared to be very pressure-agnostic, turning similar lap times with infations varying from 28 to 40 psi. After a few iterations, the Yokohama did start to exhibit some temperature sensitivity: Succeeding laps fell off a touch from the frst. It was very predictable and easy to drive at the limit close to the cones. Final skidpad results landed it in the middle of the pack on average, but it delivered a few fyer laps that were among the best of the bunch. That ease of use showed up again on the test course, where both drivers adapted quickly. Compared to the Rival, the Yokohama was better at putting down power and was much more intuitive in transitions, requiring way fewer mid-course corrections. Still, our expert driver posted inconsistent lap times– although they were still fast. Our guest driver, who had signifcant prior experience with this tire, logged tightly grouped times. Ultimately, for each driver the tire was a little slower than the Rival on average, but it came out ahead on best run and best lap. The biggest news regarding this tire may be its offcial treadwear rating: It only carries a 180 UTQG number. The AD08R can be used for events that still only require a treadwear of 140, but the trend lately has been upward for most rule makers. Although the AD08R feels like a 200-treadwear tire, its maker– unlike Hankook and Toyo–seems uninterested in rerating the rubber. Based on our experience–we ran this tire in the 2014 Tire Rack One Lap of America to great effect–the Yokohama's longevity falls near the Hankook RS3V2 and Dunlop ZII Star Spec range.