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| © David Dewhurst The 1992 Yamaha GTS1000 and the fight against the fork |
By Jack Baruth, Cycle World
[post_ads]You can be ahead of your time, you can build a better mousetrap, you can have a VPN connection straight into the distant future—but if you fall short on execution, your chances of success are identical to those of Icarus and his flight to the sun. For the first 300 years after its invention, the wheel was used only for making pottery. Nobody could figure out how to make wheeled carts equal to the durability and versatility of sleds on runners. The obvious conceptual superiority of the wheel must have been plain to all, but the successful execution of that concept took more time than the transition from the Pony Express to an SR-71 Blackbird.
By the same token, it’s universally acknowledged that the motorcycle fork is a thoroughly unsatisfactory idea. There are multiple reasons for this. It gives the wheel tremendous leverage against the headtube, while offering virtually no lateral stiffness. The steering geometry changes directly, and considerably, with load and travel. Last but not least, you have the engineering nightmare known as “stiction,” which is the resistance caused by bending or flexing of the fork in its travel. Unlike a shock absorber in a well-designed car, a motorcycle fork operates at an angle to the forces acting on it. The more fork rake you have, the more stiction you’ll have, and there’s no cure for the disease.
Or is there? Alternative steering and suspension solutions for motorcycles have surfaced with slightly more than Loch Nessian frequency over the past hundred years, starting in 1919 with the 221cc Ner-A-Car that steered the front hub via a swingarm-and-linkage arrangement. From time to time, somebody would create a one-off Grand Prix racer or concept motorcycle that either steered the hub directly or manipulated a vertical control arm to which the front wheel was mounted. The most visible examples came from the motorsports arm of the French petroleum company Elf, which built a series of forkless racers in the ’70s and ’80s, and from the Italian chassis-maker Bimota, which sold a couple hundred examples of the hub-steered Tesi from 1990 through 1994 at a sticker price that discouraged all but the truly committed. It wasn’t a toy, per se, but it was an extraordinarily fussy and maintenance-intensive machine.
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[post_ads]You can be ahead of your time, you can build a better mousetrap, you can have a VPN connection straight into the distant future—but if you fall short on execution, your chances of success are identical to those of Icarus and his flight to the sun. For the first 300 years after its invention, the wheel was used only for making pottery. Nobody could figure out how to make wheeled carts equal to the durability and versatility of sleds on runners. The obvious conceptual superiority of the wheel must have been plain to all, but the successful execution of that concept took more time than the transition from the Pony Express to an SR-71 Blackbird.
By the same token, it’s universally acknowledged that the motorcycle fork is a thoroughly unsatisfactory idea. There are multiple reasons for this. It gives the wheel tremendous leverage against the headtube, while offering virtually no lateral stiffness. The steering geometry changes directly, and considerably, with load and travel. Last but not least, you have the engineering nightmare known as “stiction,” which is the resistance caused by bending or flexing of the fork in its travel. Unlike a shock absorber in a well-designed car, a motorcycle fork operates at an angle to the forces acting on it. The more fork rake you have, the more stiction you’ll have, and there’s no cure for the disease.
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| © David Dewhurst While composed under hard braking, the GTS1000 yielded numb steering feel compared with its forked competitors. |
Yamaha’s GTS1000 sports tourer, by contrast, was intended to fill the same niche as the contemporaneous Acura NSX supercar: exotic technologies wedded to bulletproof reliability, sold at a stout but not prohibitive price, and financed to some degree by an exchange rate that made Japanese products extremely attractive to American customers. The engine was a seriously, almost criminally, detuned version of the five-valve 1001cc inline-four from the FZR1000, with fuel injection standing in for the FZR’s Mikuni carbs. The 100-horsepower rating was not calculated to raise pulses, but an industry-first fitment of a three-way catalytic converter was an obvious nod toward a changing market in which motorcycles would be expected to do their share for the always endangered environment.
Yamaha’s GTS1000 sports tourer was intended to fill the same niche as the contemporaneous Acura NSX supercar: exotic technologies wedded to bulletproof reliability.
If the rest of the bike appeared to see even further into the murky future, it was because it stood on the shoulders of a self-taught engineering giant. James Parker’s company, Rationally Advanced Design Development, secured a patent for a relatively simple “steered upright” swingarm in 1984. It dispensed with the complex rod-and-bell-crank arrangements used previously (and afterward) by other hub-steered bikes, substituting a telescoping steering column that connected to the front swingarm. This promised nearly infinite adjustment possibilities, and indeed the Yamaha Morpho show bike of 1989 used its RADD system to allow just that.
Yamaha’s GTS1000 sports tourer was intended to fill the same niche as the contemporaneous Acura NSX supercar: exotic technologies wedded to bulletproof reliability.
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| © David Dewhurst It took some 15 years for Yamaha to translate American inventor James Parker’s RADD system into production, twice as long as the machine stayed on the market worldwide. |
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The GTS1000 didn’t have any adjustability, but it did feature a unique Omega frame design where the engine sat as a stressed member between front and rear swingarms connected by a half-circle frame whose shape mimicked the eponymous Greek letter. The resulting appearance was utterly unique, even if Yamaha seemed determined to minimize the visual impact via uninspired bodywork that looked like a late FJ1200 left outside in the sun to melt.
At $12,999, the GTS1000 was a few grand more expensive than its sportbike cousins or Honda’s well-received ST1100, which it fought to an approximate draw in our March 1993 issue. We praised the Yamaha’s unmatched composure under heavy braking, while expressing reservations about parking-lot maneuverability and a numb, disconnected steering feel—both of which were direct consequences of the RADD front end.
Later on that year, the GTS1000 shone in a five-way comparison test. “A military fighter locked on target” was the staff consensus, but that focus came at the cost of last-place rankings for comfort and ergonomics. A 10,000-mile long-term test was guardedly positive: “May be worth every penny.”
At $12,999, the GTS1000 was a few grand more expensive than its sportbike cousins or Honda’s well-received ST1100, which it fought to an approximate draw in our March 1993 issue. We praised the Yamaha’s unmatched composure under heavy braking, while expressing reservations about parking-lot maneuverability and a numb, disconnected steering feel—both of which were direct consequences of the RADD front end.
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| © David Dewhurst The RADD system meant the frame could be lower and smaller than what’s needed on a standard bike. The result was the GTS1000’s Omega frame. |
Alas, the sheer volume of pennies proved to be an issue for potential buyers, whose enthusiasm for the slightly porky Yamaha often did not survive the discovery that it was priced more or less heads-up with the BMW R1100RS. It was withdrawn from the American market after its third year, surviving overseas without significant updates until its discontinuation in 1998. There was no successor. Self-consciously aimed at the future, the GTS1000 didn’t live long enough to get there.
Yet time has been kind to this dual-swingarm iconoclast. The visual uniqueness of the Omega frame makes it a first-call platform for custom builders looking to make a dramatic impression. There is at least one company building brand-new takes on the idea, complete with a re-engineered hub-steered front wheel and the engine from a V-Rod. There’s also still solid demand for the original bikes; an active owner community keeps the values relatively high, and used examples are usually sold before they are formally listed.
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The forkless front end is, no doubt, the future of the motorcycle—and to paraphrase Charles de Gaulle, it might always be, despite the best efforts of a reanimated Bimota and its brand-new Tesi 3D supernaked. Still, just a few minutes with a well-maintained GTS1000 is enough to make you wonder why the rest of the industry couldn’t follow Yamaha into that future. It’s not too late. After all, the wheel took 300 years to catch on.
Yet time has been kind to this dual-swingarm iconoclast. The visual uniqueness of the Omega frame makes it a first-call platform for custom builders looking to make a dramatic impression. There is at least one company building brand-new takes on the idea, complete with a re-engineered hub-steered front wheel and the engine from a V-Rod. There’s also still solid demand for the original bikes; an active owner community keeps the values relatively high, and used examples are usually sold before they are formally listed.
[post_ads_2]
The forkless front end is, no doubt, the future of the motorcycle—and to paraphrase Charles de Gaulle, it might always be, despite the best efforts of a reanimated Bimota and its brand-new Tesi 3D supernaked. Still, just a few minutes with a well-maintained GTS1000 is enough to make you wonder why the rest of the industry couldn’t follow Yamaha into that future. It’s not too late. After all, the wheel took 300 years to catch on.
