Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
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VOLUME 57 ISSUE 6 FEBRUARY 11, 2020 P97 The DT4's rubber compounds differ from those of the DT3, as well. Instead of the three compounds used previously, R5 (soft), R8 (medium) and R10 (hard), there will be only two, R5 and R9. The R5 is pretty much as before, a slightly softer tire for slower, less-abrasive tracks. The new R9 is a hybrid of sorts, a mixture of the old R8 and R10 compound characteristics, and a tire that can be run at a wide vari- ety of Mile and Half-Mile venues. Thanks to clever compounding, the R9's performance envelope is wide enough to allow it to be run at medium-speed, medium- abrasion tracks where the R8 was used previously, but also wheels. The benefits are less overheating, cooler running and improved puncture-resistance via the inner air liner/bladder. "Riders and techs can now bet- ter control tire pressures," says Bell, "since you don't have a tube sliding around and flexing and generating excessive heat inside the tire, especially when the big bikes run on the mile tracks." Riders who've tried the new tire are cautiously optimistic. "I did some testing early on with the new compounds," said multi- time Grand National Champion Jared Mees, "and liked what I felt. I did a 30-lap stint at speed on a mile track and they felt tube; no issues there. The safety issues, the cooler running, all good. And AFT was right with us there." AFT's Michael Lock is certain- ly in agreement. "The 2020 sea- son hasn't started," he says, "so we don't really know how things will shake out. What I do know is that Dunlop have improved the tire in every area. If you can improve in all those areas on your first try, it's a good effort, though it also means that maybe the old tire wasn't as good as we all thought it was! "So yes," Lock adds, "we are looking forward to the 2020 sea- son, and we are very happy with Dunlop's support of our series "WHAT I DO KNOW IS THAT DUNLOP HAVE IMPROVED THE TIRE IN EVERY AREA. IF YOU CAN IMPROVE IN ALL THOSE AREAS ON YOUR FIRST TRY, IT'S A GOOD EFFORT, THOUGH IT ALSO MEANS THAT MAYBE THE OLD TIRE WASN'T AS GOOD AS WE ALL THOUGHT IT WAS!" — AFT CEO MICHAEL LOCK on high-speed, high-heat and high-abrasion racetracks such as Springfield and Oklahoma City, where the R10 had been mandated for safety. "Early on we tested the new compounds in existing [DT3] molds," says Buckley, "and then moved to new [DT4] molds as we progressed in our develop- ment. Riders didn't much like the R10, but we're confident they'll like the new R9 a lot more." Finally, the DT4 is a tube- less design, though it can still be used with a tube on smaller displacement bikes without cast good, really consistent." Davis Fisher reported similar findings after an off-season test on the final version of the DT4. "I did a 25-lap main event simulation and posted my fastest time on the second-to-last lap," he told us. "The tire never did go off, never got greasy, and that sort of consistency is a good thing." "We wanted to be state-of- the-art here," says Buckley. "We wanted to bury that [tube-tire] dinosaur! Most teams are run- ning cast wheels now, and those running spoke wheels on AFT Singles machines can still use a and its extensive R&D efforts here. The company has excel- lent engineering and testing fa- cilities right here in the U.S. and a solid presence at the races, and if tweaks are needed, they can handle it. Dunlop is helping us take American Flat Track to a new level, which fans will see in the coming year." It's a partnership that's result- ed in the first all-new dirt track tire for professional competition in four decades, all of which means things are going to be extra interesting come the 2020 Daytona TT in March. CN