Cycle News - Archive Issues - 1990's

Why are 500cclap tim eson the rise? ============ =======----=---------:-;----:---:--:answers, everyAmong the variety of --"--~~ Honda 's idea By Mich ael Scott Photos by Gold & Goose as t year it was a m ild puzzl e . This year it has turned from ridd le to cris is. Why are th e 500s getting slower and slower? The person or team who can find the answe r to this vexing ques tion will reap great rewards, for pr esumably they will also find a way to reverse the trend, an d will start winn ing races at once. There is no longer an y question that there is a trend. For a whil e it was possible to make excuses bl am in g isolat ed local problems - tracks bumpier, surfaces mo re slippery, wind in the wrong direc tion, less time to pr actice, etc. The lie has be en given to all, most espe cially this L year by the 250s and 125s, which hav e been smashing lap records w ithout me rcy on the same tracks in the same weather conditions. Nowhere was this more clear than at Donington Park, where although Kevin Schwantz's pole position time was threetent hs of a second inside that of Eddie Lawson's Cagiva the year before, it was more than half-a-second behind his own pole of '91. And his lap record , also set in 1991, remained quite inviola te, with Luca Cadalo ra's fas tes t lap of th e race notably slower at 95.012 mph compared with Schwantz's 96.106 mph two ye ars before. And ye t all th e othe r numbers suggest otherw ise. The 500s of 1993 are better in every q ua n tifiable respect than their counterparts of 1991: more powerful, wi th a w ider spread of po wer, more precise throttle response, stiffer chassis, fast er gears hifting, better brakes, more hi ghly developed susp ens ion an d improv ed tire s. It is certai nly ha rd to know what else do you hav e to d o to improve all-roun d perform ance. The biggest difference between th en and now is the u niversal ad option last year by all the factory teams of Honda's close firin g orde r d rone-en g in e. This more user-friendly engine not only gives the rear tire a much easier life but as a corollary also gives the rid er more con trol at the cru cial phase of cracking the throttle open out of a corn er. Yet many peopl e ar e reluctant to blam e the Big Bang directly for the lap-time deterioration, pa rticularl y since it has won almost every race since it fir s t a p p ea red a t Suzuka at the beginni ng of last season. Paddock theor is ts hav e a number of explanations (one wag even pu t it down to global warming), which boil down to the following: 1: The riders aren't trying as hard as they used to. 2: The bikes aren't trying as hard as they used to. Which m a y be tru e, but d o esn ' t ad dress the more vital question - w hy not? one prefaces their own theories with the obligatory remark: "If we knew w hy, we 'd be able to do someth ing about it." It is tempting to look first a t the tires, becau se '91 was a rather diff erent yea r from 1993. It was prece ded by Michelin's pr etended wi thdrawal from racing, an d all the top teams excep t for Honda used Dunlops, which then and now were less grippy than the Michelins, but m uch more user-friendly in the sense tha t they were much mor e controllable when slid- ing, an d as a resu lt much less likely to p itch an erran t rider into a dangerous high-side crash. In '93, all the 500 tearns excep t for Wayne Rainey 's Team Roberts Yamaha are bac k on Michelin. But then again, the Dunlop-shod works bikes are suffering the sa me malaise as the others. D unlop su premo Jeremy Ferguson was only really sure of one thing: "Tires are mu ch be tter now than they were then . The size is slightly larger, at 190 section now compared with 185 then, on a 6.5-inch rim. If we were just to bri ng out '91-spec tires in place of ou r new ones, the riders would soon be screaming and shouting." Sure ly so, bu t would they be circulating at '91 lap limes? Well, probably not , g iven the cha ss is and engine d evelopments since those tires were current. "The compu ters tell us no w that the bikes are accelerating quicker, running h igher top speeds, and braking later. The time is obviously being lost in the middle of the corner. "Definit ely, 250s are running high er corner spee ds than 500s, and looking at their lap times at some of the slower circuits, if they had a little bit more grunt, they'd be faster." Jerez is a regular favorite for this line of ar gument, wh ere this year Tetsuya Ha rad a's 250 pole qualifyin g time wa s within 1.3 seconds of Schwantz's 500 pole. Not only would the 250 have been on the second row of the 500 grid, but Harada' s time was within a quarter of a second of th e ex isting 500 lap record (which, to the relief of all, was one of the few actually broken this year). Ferguson also cites Suzuka. "Jere z is twisty, b ut Suzuka has a good lo ng straight where the 500s sho uld really gain a big advantage." In a two-m inute lap time, Harada's best race lap this year was only just over a second slower than Schwantz's. " If th in g s carryon as they are," Ferguson con tinued, "in two years time there'll be a crossover between 250s and 500s, and there must be a good case for a factory to build a halfwa y house - like of a 375, bu ilt to a lower minimum weigh t limit." The notion of a "power-up 250" - just such a b ike as Bimota has long promised , but failed to d eliver, gains creden ce the more people you talk to. To Team Marlboro Roberts crew chief Mike Sinclair, a long-stand ing GP guru, the destruction of lap times is the result of a combina tion of facto rs - torquier engines and mismatched front/rear tire wid ths not really .sui ting the smoother ridin g style the extra torque enab les. "A 500 has a truck tire on the ba ck and a bicycle tire on the front - it' s meant to go round corners on one w heel : sta nding on the fron t on the way in, the n up on the back on th e way out. Whe n yo u try and go ro u n d on two wheels, it doesn' t work so well. The riders hav e always com plained of a lack of side-grip, so you give th em si de g ri p and they go slower . The ra ces Rainey has d on e w ell a t thi s yea r wer e the.ones wh ere he com- . pla ined that th e tires had gone away." It is to ta lly bizarre tha t technical improvement should lead to a reduction in pe rforma nce, yet Fre d die Spencer has ways of making ma ny thin gs plausib le. Sinc e he was (with Kenny Roberts) responsible for the las t sudde n step in 500-class lap times, and also has (ad mittedly limited) expe rience on a mod ern GP bike, he certain ly has a broade r perspective than any other 500 ride r. Spen cer's paradox is that in making the bikes easier to ride as we ll as capable of higher speeds, eng ineers have made it harder to find and to ride to the limit. "The limit used to be clearly de fined ," Spencer said. "You could feel just where it was and you cou ld ride there. Now the bikes are more effective, an d the limit is much harder to find. "When I go t on Erv ' s NSR at Kyalami a t the end of last year to test it, it was a lot easier to ride than the bikes o f the mid-'80s. But th e resp onse was less direct. The ex ha ust note plays a par t he re. With a p eaky e ng ine, yo u could snap the thro ttle and hear wha t it was going to do. The new engines don 't ha ve that so und to judge from - the y don't communicate so directl y w ith the rid er. "You al so ha ve to look at corner speed s . With more power lowe r and lower down the rev range , that restric ts your ability to open the throttle earlier. You ta ke it to th e poin t of w heelspin, then you hav e to wa it." Former 250cc champion and 500ccclass crash-tes ter Christian Sarron, si tting alongside, agrees with the importa nce of knowing the limit. "I crash ed much more often wh en] was no t at the limit, if] wasn' t confident in the bike or the tires. I was safer at the limit." We'll come in time to the current riders, bu t first the view of Kenny Roberts remains an esse n tial when considering any racing question. He has long been a g reat champion of not res tric ting the 500s, bu t now finds himself somewhat bemused by the belief that a big part of the p ro blem is a n emb arrassment of ho rsepower. u.~:fu~~,~!Y,"I~~ ; them . Bu t the 500s are probably too powerful. If you reduce d the ou tp ut, yo u' d get better lap li mes. We went through the same thin g in the 70s with the TZ750s," he said. "The AMA reckon ed t hey w er e to o d ange rous, and mad e a regulation for inlet reslrictors to cut the power. And we went faster." Th e nature of Big Bar.g power was also important, "Drone engines give better traction," Roberts added. "Wa yne's complaints now are all about the front end pushing." Bu t while he is convinced ' that inlet restrictors or a switch to a 375cc powerup "250" would result in an insta n t improvemen t in lap times, he remains de voted to the current horsepower race. "With rest rictors, yo ur to tal la p tim e ' may be better, but you'd never win the race . A current b ike ca n accelera te so much faster tha t they 'd always be able to ge t in the wa y on the race tr ack . The sa me goes for a '91-s pec bike. As it is, Wayne was using a chassis designed in '91, for less po wer an d less traction - and getting bea t. "We'll find a way rou nd the problem . If our bike was better it woul d he lp . Maybe it will tak e a new rider who is p repa red to pu sh the front ha rder - like Mick Doohan did at the start of last year. Even when I was racing, being pr epared to push the fron t more was always the ~ C'fJ 0\ 0\ .,.....; -. 00 H ..g (J) l=; (J) .... 0.(J) Cf) 'way to go fas ter, from one year to the next." So is it just because the current gen era tion has been allowed to become com pl acent? Cer ta inl y it is th e sa me t hree. men - Ra iney , Sc h wa n tz and Doohan - who are failing to improve on their own pe rformances, and Sarron for one is q ui ck to poin t o u t th at th in gs migh t be d ifferen t this yea r if Dooh an was fit, and if Wayne Gar d ner and Eddie Lawson were still around to force the pace. Schwantz allows there may be some truth in this view . "We used to crash more o ften, so maybe we 'v e all pulled back just tha t little bit for th e sake of safety, and also to pu t together a more consistent championship cha llenge." It is in an y case in lin e w ith his resolv e o f three years ago, to attempt only the possible, and to win at the slowes t possible speed. Doohan tends to reserve his judgement, mer ely pointing out th at it .w as after his big accident last year that the times really sta rted to erod e very seriously. He leaves others to draw the conclusion that .if he had not su ffered the major interruption to his career imposed by his Assen leg injury last year, he 'd be whacking away the lap records this year as if he were hardly trying. There remains one fin al ques tion. Does any of this matter? One is forced to reply: Not very much, for two reasons. The first is that the actual racing is as close as ever its been in recen t times, and in no way less exciting becau se of a few lost fractions of a second. The seco nd is that it is sure ly jus t a developmen ta l hiccup - one of t hose blips on a rising graph tha t se rve to allow everyo ne to ge t their breath back before the next surge forw ards. Bu t even if th is is n o t true, the prospect remains pleasing. One can only relish the prospect of a lightweight twincylinde r 500cc-class racer that can trul y mix it with the big-ban g chargers - and then enjoy for the tech nical bat tle that will sure ly follow. CN '39

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