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/126789
The Trihawk has exceptional cornering abilities and will out-perform most four-wheel cars in skid-pad tests. It looks strange. however. Harley-Davidson's Trihawk A look at three-wheeled motorcycling Part 1 By Jim Wolcott "Looking at the Trihawk is sort of like taking the Rorschach Test. You know - the one where a psychiatrist shows you an ink blot, and asks what you see. What does the Trihawk look like to you?" John Brusky, Sales Director of Harley-Davidson's recently acquired Hawk Vehicles, Inc., ,26\ couldn't have done a better job of describing the curious vehicle before me. There are no hard and fast definitions as to where the'Trihawk fits into the spectrum of transportation. For the government, it is defined as a motorcycle. For the objective driver, it is'a sports car. For the few who own one of these strange vehicles, the Trihawk is fun. In fact. it's a blastl The Trihawk was conceived by Lou Richards: a mechanically-inclined auto buff who, some years ago, devised a machine to mass-produce hamburger meat patties. The booming success of several fast food chains made Richards a millionaire ... and a man in search of a new project. While sailing in the Bahamas some six years ago, Richards took note of a curious four wheeled auto called the "Moke." The Moke is a small utility vehicle manufactured by British-Leyp l.lJq,d~t~'?Pf4l\s •. a simple, 'round- town car. The Moke most closely resembles a surrey with a lawnmower engine; a vehicle which, in this country, is best known through infrequent appearances on theTV show "Fantasy Island. " "What if ... " reasoned Richards, "someone were to build a domestic Moke? A small, lightweight vehicle that would be inexpensive to own and operate? A vehicle that would be fun to drive?" Sketches were made, the midnight oil burned, and a prototype soon wheeled from Richard's garage. Shortly thereafter, the Department of Transportation delivered a list of regulations to which Lou Richards' tiny four-wheeler must conform. The idea of producing a lightweight and inexpensive auto was stillborn; an idea smothered by an avalanche of red tape. However, buried deep in those smothering regulations was a listing of the various requirements for motorcycles. Part 571 ofthe Federal Motor Vehicle Safety Standard legally defines (, ~fIll~lpr~llj: ;'lI49tprcyc~tf:- J,ljejlllilig used for steering. Of course, this makes street trikes ideally suited for wheelies - and less than ideal for any maneuver which involves going around a corner. For a three-wheeler, placing two of the wheels up front changes the whole picture. For this layout, there's ample tread rubber to support the weight transfer of the most violent panic stops. In addition, if the steering wheels are also the driving wheels, the vehicle will "pull" itself through the corners, wi th less danger of breaking traction. Should the brakes be required in the midst of a turn, weight transfer will squarely load the outside front wheel. Surprisingly, a three-wheeler can offer some advantages over a traditional au to. Most obvious is that a three-wheeler can be substantially lighter than an auto. Missing is not only the one wheel, but the suspension and framework to support that wheel. The body of the vehicle can be abbreviated, simply because it doesn't have to assume the boxy, rectangular configuration of one-wheel-at-eachcorner automobiles. More important than the potential weight savings is the nature of the suspension loading with a threewheeler. All of the roll resistance is easily handled by the two-wheeled end of the vehicle -leaving the trailing third wheel virtually free from the torsional loads involved with cornering. The end result is that a three wheeler is subjected to less chassis flexing and twisting than a fourwheeled auto, even though the vehicle can generate impressive g-forces while cornering. The bottom line is that threewheelers are not necessarily a design compromise of four-wheeled automobiles. In the late 1970s, the Department of Energy, having been swamped with proposals for energy-efficient three-wheeled vehicles, contracted Paul Van Valkenburgh (noted auto writer, race car engineer, builder and driver) to perform tests on the stability of these machines. His final report to that government agency ran more than a hundred pages long, butin the final analysis, Van Valkenburgh stated that "... a properly engineered three-wheel car can be made as stable as a properly engineered four-wheel a motor vehicle with motived power, having a seat or saddle for the use of the rider, and designed to travel on not more than three wheels in contact with the pavement." Further, as far as the EPA was concerned, the Code of Federal Regulations defines a "motorcycle" as "... having a headlight, taillightand a stop light, having two wheels, or three wheels, and a curb mass of Jess than 680 kg (1499 pounds)." These defini tions of a "motorcycle" practically pave the way to the construction of a small, sporty and lightweight vehicle. For instance, motorcycles are free from the encumbrances of five-mph bumpers, don't have to meet standards for side impacts, and have no roll-over/crush specifications. Modern automotive engines will easily meet the EPA's motorcycle emissions requirements - usually without the hassles of air-injectors and catalytic convertors. Motorcycles are also (comparatively) free from untold thousands of nit-picky regulations that drive up the cost - and complexity - of contemporary automobiles. After reading through these regulations, Lou Richards' project changed from one of small, lightweight and inexpensive transportation, to one of small, lightweight and SPOTty transportation. A three-wheeler that, while technically a motorcycle, would be a throwback to the era of lightweight European sports cars. But what about a three-wheeled vehicle? What about handling? Stability? Good questions. In the case of a three-wheeler, handling and stability are a function of configuration. Currently, there are two three-wheel layouts: one which positions two wheels to the front, and the other with two wheels to the rear. As it turns out, the two wheels to the rear configuration (like the VWpowered custom street trikes) can be problematic. With a single (and often skinny) front wheel, weight transfer during braking can cause the front wheel to skid - resulting in an instant loss of steering control. With this layout, braking during cornering results in an overturning weight transfer which - at best - tends to lift the inside rear wheel. Street trikes make the best of these unwelcome characteristics by placing most of the weight over (or behind) the rear wheels to minimize the loading on the front wheel. In fact, the front wheel becomes l1iHIFJrIlf?r~j,tJlaA,~ ;j·,w.~JntTj,HP( car." I Once Lou Richards decided to pursue a three-wheeled vehicle, he contracted noted race car designer Bob I Mc}S~e, W,'t jS!l\ljI~ \'1 epgiqC;lOring