Cycle News - Archive Issues - 2000's

Reignin8 U.S. National Trials Champion Geoff Aaron claimed a double win at rounds one and trvo of the NATC/AMA National Tiials Series held at Holbrook, Arizona, April l-2. Aaron is in pursuit of an unprecedented loth National title in 2006 and got off to a good start on the lar8e, Srippy rocks of the Arizona venue by toppin8 his ERE/Gas Gas leammate Keith Wineland by 8.5 points to take Saturday's win. Cody Webb onished third, ahead of his Sherco USA teammate Bruce LeRiche, with Chris Florin, ridinS for Gas Gas USA, rounding ouc ahe top five. Geoff Aqron won the opening two rounds of lhe Norionol Triols Series in Arizono. Aaron was even more impressive on Sunday, finishing out the three-lap course wilh a clean final loop and Posting a total score that was exactly half that of Florin in the runner-up position. LeRiche finished third on Sunday, with Wineland and Webb rounding out the rop Rve. "l definitely wanted to start off the season stron8," Aaron said. "We've been really busy doins shows and demos, but I have been for- tunate to be able to practice at the Trials TraininS Center in Tennessee, and I think that helped me out, because I was able to stay on the bike all winter long." "These sections suited me," Aaron added. ,They were dry ard grippy rocks and thar ls sim- ilar ro lvhere I practice in South€m Califomia." \Mth the two wms, Aaron leads the senes standings wirh 50 points, followed by Wneland wi$ 40. Florin and LeRjche ar€ tied for third place with 38 points, while Webb sirs in llfth with 36. Sampey Rolls On There is srill a long way to go. but tlvo ! races into the 2006 NHRA POWERade DraE Racine season, Angelle Sampey is already the overwhelming favorite to caprure her fouEh Pro Srock Motorcycle Championship. For lhe sec- ond time in the last four years, Sampey opened the season wiah back-co-back wins after claimint the O'Reilly Spring Natronals tide at Houston Raceway Park on April 2. Two weeks earlier, she won the season opener in Gain€sville, Florida. "The competition in thrs class has tor- len so routh thar iCs hard to win one race, ler alone nvo," Sampey said. l m not sur- pflsed in the ream accomphshing this, but I thought maybe I d win one and Antroo [Brown, her teammate] \,Yould win the olher. I keep telling [crew chiefl Steve Ta[a8ha ro take a vacation, because all he does is work, but maybe if all that ',,{ork results in wrn after win. then I guess we shouldn t change aq/thint." After finishing rhird last ),ear, Sampey and her U.S. Army team have benefired from an off-season rules change that helped close the gap between the Suzuki and Harley-Davidson entries by allowint inline four-q/linder bikes !o have an addi- tional nine cubic inches. POWERade points standings after iust two races. lncidentally, it alro marked the lifth time in the last six years that a female rider has won the Houston title. After a semiflnal finish in Gainesville, Hines reached the final round for the eighth time in his caree[ "We've strug8led a little, but our pro- Sram is senint to come around,' Hines said. 'Afrer two races. we're actually ahead ofwhere we were last year. so I still feel pretty good abour our chances to win the championship. lt's a long season, and I know you still haven't seen the best of our team yet- \rye've got a month before the next race in Atlanta, and that iust gives us more time to make our bike quicker." Kefin MaKennd J a Sampey qualified in the number-one position for the 38th time in her career, with a 7.03, and she began elimina- tions with a 7.ll in her round- one win over former NHRA champ Geno Scali and a 7.18 in round two to beat Mike Berry's Suzuki. Sampey remained consistent with a 7.16-to-7.22 win over Screamin' Eagle Hariey- so tough that it's really an accomplishment to beat them. They think we hate them, but we don't. I hon€stly appre- ciate the competition." With her 39th aareer victory in just 137 career starts, Sampey now stands ninth in NHRAs all- time wins list. She has also opened up a 63- point gap over second- placed Hines in the collides with anorher resonant frequenry - usually the frequency of rhe chassis The effecr is to destroy 8rip, and the tire literally chatters across the surface of the track, and that scops the rider from putting down power and thus destro/s any hope of a tood lap time. So, af you have two frequencies that sud- denly (ollide, you have a massive problem. One of the logical solutions is to chante one of the frequencies. The [ire companies don't like to try to modify their tires, because i!'s very easy to lose an avvful lot of grip with a few small changes, but you can try to change the chaisis - by changng its frequency, ius! like loosening and tightening that guitar string. And that is what Yamaha was doing at lerez. This year the Yamaha chassis has a differ- ent, stiffer frume near the steering head- The swinSarm ls also stronter, and it's quite possi- ble that one of these changes has moved the overall.hassis frequency into the danser zone. Jerez has a whole series of comers where a rider is fully leaned around fairly dow comers - exactl/ tie riSht sort of speed to trigger the vibration. Yamaha had problems in a few cor- ners a! Qatar and l.{alaysia. but these circuits have less of the wront comers than Jerez. The Yamaha has a unique chassis. lt is not only the best-handling bike out there. but it is also one of the mosl easiry adjustable. The chassis ha5 irs main engine mounts down at the front of the crankcases, and also has sec- ondary ones just behind the cylinder head. Yamaha's chassis desitn appears to allow them to adtust rhe riSidic/ of rts chassis. Lrsing different materials for the rear-en8ine mount means they can make the chassis softer - and a softer, more compliant chassis miSht not resonare rn the same way, Those same enSine mounts would allow Yamaha's engineers to change the frequencies of thints such as the engine; hung as it is under the main spars, it is going to have a natural desire (o vibrate. Yamaha tried hard at Jerez, and all the classic chassis-tuninS ideas have been tried, different spring rates and different weight dis- tributions have been utilized (with more weitht going to the front) - so much so that Rossi wa5 complaining of no rear grip at all. Addirionally, Yamaha has been trying differ- ent rear-cylinder head mounts, and changint these .an change the vibration frequency of the chassis and the engine. These brackets normally help maintain cha5sis ri8idity by stop- ping the chassis from twistint. They lie on a straisht line above the rear rire's contact patch and ahe swingarm pivot. Loos€nint these, or using different malerials in the mounring bracket, would also have the same effect as tightening and loosening that guitar string. An item's natural frequency is set by both its ma5s and its rigidit),. The en8ineering solu- tion is to change the frequency of the various parts of the bike by chanSinS their rigidit),, and that is what Yamaha was trying to do all the way throu8h practice untilSaturday night. But it didn t work. On Sunda), morning, the old- fashioned race en8ineers were given ago, and both Rossi's and Colin Edwards' bikes came out with lead or steel filling the normally hol- low lightweitht axles. Sure, it adds to the weight of (he bike, but it fundamentally chanSes the frequency ofthe cha5sir, and in a situation like this, that matters a lot more! Rossi took the heav)/ axle into the race- lt made a difference, but all he could manate was the I lth-fastest lap afler being reletated to lhe back ofthe lleld after a clash with Toni Elias. Thus, there is a bir more work to do before this problem can be persuaded to go a!1/ay and stay away. Rossi acknowledted that Yamaha has a problem. "We trla lot ofthin8s, butwe and Michelin could not Und a solution in six days of testing on this track with this condition," he said. "For sure, we are not in a very Sood sifiration now. We try a lot of thints, but it is bigger than us. First we have to find our normal speed. lt is a big question mark. Together with Yamaha. we have to find a solution. lf we find it on a Fraday mornin8, and if you arrive at race time with chatter, it is too late to llx. lt does not respond to springs and chassis position. lf we get this again, we are f*& ed." Neil Spolding CYCLE NEWS . APRlL l2,2006 I I Davidson's GT Tonglet in the semifinals. Waiting for Sampey in the final round was TongleCs Screamin' Eagle teammate, rei8ning POWERade champ Andrew Hines. Fresh off wins over Matt Smith. Antron Brown and Chip Ellis. Hines got off the starting line a fraction of a second ahead of Sampey, but she passed him before the finish line to lake a close 7.14- to-7-20 victory "Beating both Harleys today is iust icinS on the cake," Sampey said. "l've raced a Suzuki since I first got inro Pro Stock Motorc),,cle, and I never want to change to another band. We fought hard for some changes to help level the field, and it feels Ereat when we .an beat the Hadeys. I told Andrew that their team is him from getting out on qualiliers on the ,inal day. "Not the best day of my life, but I guess this sort of thing can happen in our job," Muggeridge said. "l knew I was hurt sFaight away; the pain was quite strong. Now all I can do is to relax so that I can be back in top form as soon as possible. Tomorrow lwillgo to a spe- cialist in Switzerland and we will see what th€ latest situation is. I want to thank the doctors from the Clinica Mobile who have been wonderful today." MutSeridSe's Winston 'Ibn Kate Honda teimmate ,emes Toseland prob- ably expected a tougher-than-normal test at Valencia, to some degree, as he rates it the most diflicult racetrack for his Honda He had (o battle to set a l:35.879 Good enoqh for l6th place), but he also did that on Tace tires, as he fell in an incident separate from Muggeridge's but at a very similar early iuncture. Fabien Foret proved that full factory hoEepower is maybe not quite needed for the good privateers, and he went l3th out of 28 on his Belgian-tuned GSX-R He wa! one place ahead of the experienced Marco Borciani and ttvo up on former Superstock king Vittorio lannuzo. Norick Abe, despite a fever, did a whopping 200-plus laps, using different engine specs that he did not rate :tny more highly than the previous ones. His teammates, regular rookie Shinichi Nakatomi and Sebastien Gimbert sub- strtute Lorenzo Alfonsi, went 23rd and 24th, respectively. Despite a strong start to his rookie World Superbike season thus far, Robby Rolfo ended up 2lst in the test on his Ducati SC Caracchi mount. but he was still ahead of Pier-Fiancesco Chili, the Italian ending up in 22nd. Gordon Ritchie Aaron Off To Perfect Start __?4

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