Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/1515142
VOLUME 61 ISSUE 4 JANUARY 30, 2024 P107 "not invented here" syndrome saw Suzuki shuffle it off to the back shelf in favor of their own conventional aluminum-tube chassis. Mackenzie had prior experi- ence on another British effort, the 250 Armstrong. This used a molded carbon-fiber spine, filled with expanded foam and baked in an autoclave oven, also standard racing-car practice at the time. The Rotax-powered bikes, the brainchild of Mike Eatough, also had carbon-fiber swingarms. And they performed well, with Donnie McLeod, on the podium in Belgium in 1986, A low-budget independent effort by British designer Chris Wheatley appeared briefly in 1986, ridden by Gary Lingham, but sank without trace. The aim back then was for total chassis stiffness, to let the well-controlled suspension absorb the bumps. Chassis flex was blamed, correctly enough, for all sorts of wayward han- dling. Convention took over, while chassis design itself moved on. Maximum stiffness, it turned out, was not ideal. At the in- creasingly high lean angles allowed by tire and suspension development, too much stiff- ness encouraged what Wayne Rainey in the early 1990s dubbed "chatter-bounce," and it was only when he switched from the too-stiff factory chas- sis to a more flexible Harris version that the problem was reduced. But if maximum stiffness wasn't right, nor was random flip-flop flexibility. A chassis needed to be rigid fore-and-aft, to absorb braking loads (also in - creasing, along with better tires and carbon discs) but to flex in the right way laterally, to absorb bumps at full lean, thus avoiding chatter. It sounds simple, but it is far from it. The quest for a chas - sis that will "bend like a tree," to borrow one Japanese engineer's phrase, remains as absorbing and difficult today as it always was. Much progress has been made, all with aluminum (and for KTM, steel-tube) chassis, with carbon thought to be too stiff. But like money, in racing, more is good but is never enough. There was, however, one believer that carbon-fiber, far superior strength-to-weight, could be made to work. Ducati Corse's first MotoGP engineer Filippo Preziosi's innovative style, saw him make a minimal - ist carbon-fiber box that com- bined the function of an airbox and main chassis spar. Isn't carbon too stiff? We asked him. No, he insisted. The material is not important in itself, it is how you use it. His experiments were not successful, however, underlined by Rossi's failure to continue Casey Stoner's successes with the Desmo. Preziosi eventually paid the price, replaced in 2013 by current Ducati genius innova - tor Gigi Dall'Igna, whose prow- ess has been rewarded with the marque's current domination. The first thing he did was to revert to a full aluminum chas- sis, but was Preziosi so wrong? Stoner recently came to his defense in an interview with Ita- ly's Gazzetta dello Sport, saying that it was lack of budget that constrained chassis develop- ment. Preziosi was "very clever" but didn't have the resources to develop his ideas. Ducati's big mistake, said the Australian, was failing to support him. While carbon-fiber swingarms are common, KTM is the latest and currently the only construc - tor to delve into the black arts of carbon chassis construction. Has bike racing finally caught up to F1? CN THE QUEST FOR A CHASSIS THAT WILL "BEND LIKE A TREE," TO BORROW ONE JAPANESE ENGINEER'S PHRASE, REMAINS AS ABSORBING AND DIFFICULT TODAY AS IT ALWAYS WAS.