Cycle News - Archive Issues - 1990's

MORE SIZES, MORE COMPOUNDS The big news for the AMA riders competing in the World Sup erbik e event was Dunlop' s new 16.5-inch front tire. U.S. Dunlop technician Jim Allen alerted the three AMA teams competing of the new front , but the Yamaha team was u nable to get the rim sizes in time. Van ce & Hines Ducati and the factory Honda team , however, ponied u p approximatel y $800 ap iece for thr ee rims per rider to be on the lates t and greatest. Thou gh A nthony Gobe rt decided to stick with his tru sted 17-incher, he was the only Dunlop rider who tried a 16.5 to do so. According to Allen, the 16.5 is a relatively recent de velopment. . "They had a test befo re Donin gton (England) at Albacete (Spain) with quite encouraging results," he said. "I believe tha t (Akira) Yanagawa was the only one to race on it at Donington (May 2, 1999). The next week, in Albacete, almost everyone used it. It beca me clear qui te quic kly tha t it offered a grip ad vantage. It's basically more stable entering and finis hes the corner better; from the apex out, it sort of pulls you around the comer and you have more grip exiting the turn. Eric (Bostrom) noticed it qu ickly on the.Ho nda, because that's one of the problems they have - finis hing .the comers wit h the RC45." Vance & Hines crew chief Jim Leona rd confirmed Allen's comments and no ted a slight drawback. "The 16.5 offers more side grip," he said, "but it's heavier (steering) effort on the turn-in. An thony feels that for his style the old setup is better suited to him." Allen admitted that, "The initial turn-in (of the 16.5-inch tire) might be a little heavier than a 17inch because it 's brand-new and we ha ven ' t developed the profile like we have on the 17s." Honda crew ch ief Ray Plumb said tha t th e new tire was a positive change for their RC45. . "Eric (Bostro m) said th e 16.5 was better a t holding the line through the corner," Plumb said . "It wasn 't a qu estion of, Should we try the.17s again? We felt immediately that it was a step forward ." "Ben and Eric (Bostrom) have both tried it (the J6.5-inch front) on two quite d ifferent motorcycles and they both prefer it," Allen commented. "Out of any of the World guys that have tried jt, no one has gone back to 17s." (a privat ee r AMA Supe rb ik e rid er) , you've got a real problem there. "1'11 tell you straight out, when Dou g star ted with us in '96, we still had the World team," Muzzy said. "Doug didn't like many of the things that the World team used at that time. And in all hon- esty, I truly believe that Doug' s bike was better . I truly believe that a t that tim e Doug's bike was a better bike than what we raced World Superbike with. And I'm going to credit that to the fact that I think Doug took it in a better direction . I'm not going to knock Antho ny (Gob- Plumb also noted that since the new tire was a bit sm aller in radius, the team altered their RC45' s fron t ride-height geometry acc or d ingly. Alle n wa s underst andably evasive as to the exact dimensional differences. "Ove rall circumference is slightly small er," he said. "1 do n't want to say by how much exactly - we'll let Michelin figure that out for themselves." But the n ew fro nts wer en' t the on ly news to the AMA riders. There we re also more rear-tire choices than you could shake a stick at. Virtually all the new Dunlop rears in either World Superbike or AMA are no w 16.5 inches in diameter (actually referred to as 420mm tires, instead of 16.5-i nch ) r ath er than the more conventional 17inc h sizes. The sma ller tir es offer a taller sidewall, wh ich in turn allows mo re compliance and hence tractio n a t m a ximum lean angles, . "On an A MA weeken d, Du nlop has basica lly a so ft, medium and hard compou nd available at most tracks, with dual-compound slicks availab le at certain tracks," Alle n explained. "This weekend we have up to 30 t ypes of slicks a vailable (11 front s a n d 19 rears) and seve n typ es of rain tires available. They see more changes.in tires in three races than we see in a year. I wouldn't wan t that many tires here - I couldn't keep track of them all." ' Another factor to consider is that while Dunlop has five factory riders in World Superbike to Michelin's six, the AMA series has 14 Dunlop factory superbike riders to Michelin's two. ert), but [ th ink its well known that Anthony doesn't have a lot of experience setting a bike up or fixing a problem. Anthony basically went through the process of trying the equipment that the Japanese engineers provided. It had alread y been de cided that we (Muzzy' s) weren 't going to continue (as the World Superbike team) in '97, and so '96 was the year that the Japanese took over, so to speak. That was kind of part of our agreement. They needed to get a handle on it and they took charge in '96 and it was their program. It was still my deal, speak for the Yamaha yet because this is the first year we are working together and we have no background. We work a little bit with Scott (Russell), but (Noriyuki) Haga is much different than When World Superbike launched their new Superpole qualifying system last season, Scott. Usually the difference between 17 and 16.5 is, which det ermines the starting order for the first four rows by virtue of a single flying the 16.5 ",;11 last longer than the 17, but it doesn't lap per rider, it forced Michelin to do something it hadn't done before: d evelop a tire steer as fast, as quick. The 16.5 is specifically for qu alifying. a wider tir e, so of cou rse it's a "The p roblem before, was, we .did not bit slower, but since you have see any reaso n to d o a tire that you threw more rubber on the grou nd, usuaway after three laps," explain ed Michelin ally it w ill last longer and will technici an Jea n H er isse i n h is st ro ng have better exit grip for Ducati French accen t. "But here we have no choice for-sure, because they make the ru les that you only "The 16.5 on the bumpy race have one lap to do the time. I was a little track, it has a little bit of ad van bit not in fu ll 'ag reem en t w ith th e FIM, tag e," Herisse admitted. "Now becau se they d o the opposite of what they th e last few years, t h ey ' ve claim - (they claim that they're) trying to reduce cost, and then one set of tires to d o improved so much sus pe nsi on only one lap is maybe a little bit expensive so they don't complain so much to the p rivateer. But on the other hand, I a nymo re about the bumps. In can underst and because it is a very good th e past, yes, but now it's get - . sho w for TV. But we have no choice, we ting much better and they don't have to bu ild a tire just for this ." complain as much as the y used But Herisse went on to expla in how curto. Last year (at Laguna Seca) rent World Cha mpion Carl Fogarty, who , almost everybody use 16.5, so though he's the winningest rider in the hiswe are focusing on 16.5 here. tory of the series, has never been much of a But maybe Honda and Carl, qualifying speci alist, has had recent su cthey use 17s. If they have hard acceleration, and usually hard accelcess without using a qualifier. eration is from a .slower comer. In a slower corner, you don't need "Carl will not necessarily always use a to steer as quick because it don't feel as heavy. You usea 16.5 at this Superpole tire," Heriss e said. "Carl is able type of race track." to do that without it . He get the lasttwo Herisse also scoffs at the fuss being made over Dunlop's recent switch to 16.5 - or in pole position and he was not usin g qualifying tire, he was using - [ will say a so fter the metric system that the French prefer to use, 420mm - tires . race tire than he used in the race, but a race tire, and he still make the pole at Nurber"Kevin Schwantz was one of the first ones to use 16.5, but I forget exactly which gring and Misan o. And normally he's not a specialist for Superpole, To me, it's not year, maybe, I would say '91 or '92," Herisse said with a bit of condescension. "Kevin much in time. It mainly helps you mentally because right aw ay you could ask a lot . from the tire and especially in a bad condition. If it's freezing, the rider has not to was even using 16.5 front." Herisse also pointed out that Michelin's sizing system for their racing slicks is difworry and the tire will mak e time to get warm, so this will be read y right away. To me, , they improve lap time but not so mu ch. It depends on the race track . On the slow race ferent than the standard DOT-type system used by other companies. For instance, the dimensions of their 19/67R420 rear slick is 190mm in width, while the 67 is 670mm in track, yes, it does help, but on the fast race track, no." As opposed to Dunlop, Michelin uses both 16.5- and 17-inch rear tires in parallel outside diameter, rather than the more conventional aspect ratio of percentage of width determining sidewaII height. The 420 is the wheel diameter in millimeters. development, and which is better is largely dependent on the track itself. As for selection, Michelin had three compound choices in 17-inch rears, four for "It depends on the race track," Herisse said. "Some (tracks) are maybe always 16.5, some are always 17. And some are mixed, depending on the motorcycle. I would say their 420mm rears and three choices for their 17-inch front tire. There was also a qualithe Ducati will more often use 16.5 and the Honda will use more often 17_ I cannot fying compound available for each rear-wheel diameter as well. NEW QUALIFIERS AND CHOICES GALORE 43

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