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36-423: Just as with road outfits, early sidecarcross outfits were little more than a solo bike with a sidecar attached to its frame by metal tubes. As the sport developed, sidecarcross outfits became more integrated, although most retained a tubular structure rather than a monocoque chassis. Sidecarcross outfit configuration tends to echo national road outfits, with the sidecar fitted to the "nearside": UK sidecars are on

72-510: A drag car maximizes traction at the rear axle while countering the reactionary pitch-up torque. It generates this counter-torque by placing a small amount of counterweight at a great distance forward of the rear axle. In the airline industry , load balancing is used to evenly distribute the weight of passengers, cargo, and fuel throughout an aircraft, so as to keep the aircraft's center of gravity close to its center of pressure to avoid losing pitch control. In military transport aircraft, it

108-415: A combination of castings and sheet-metal stampings". Single-piece carbon fiber bicycle frames are sometimes described as monocoques; however as most use components to form a frame structure (even if molded in a single piece), these are frames not monocoques, and the pedal-cycle industry continues to refer to them as framesets. If a "monocoque" frame uses additional support, such as tubes or longerons,

144-441: A finite degree of built-in flex is preferable. If the handling of the motorcycle is not appropriate, it is important to check the deformation of the geometry of the motorcycle frame. This measurement can be important after an accident or before buying a used motorcycle. Weight distribution Weight distribution is the apportioning of weight within a vehicle , especially cars , airplanes , and trains . Typically, it

180-593: A season-ending Sidecarcross des Nations . The sport is very popular in Western and Central Europe, but the sidecarcross scene in North America and Australia is much smaller. The most successful sidecarcrosser in history is ten-time world champion Daniël Willemsen of The Netherlands . However, since Willemsen won six of his titles with four different passengers, the most successful team is Kristers Sergis / Artis Rasmanis . Motorcycle frame A motorcycle frame

216-413: A single spine beneath the tank. Also called beam or twin spar , two beams wrap around the engine to join the steering head and swing arm in the shortest distance possible for better rigidity. Beams are usually made of pressed metal (steel/aluminium). The trellis frame employs the same concept but uses welded members to form a trellis instead of pressed metal. Antonio Cobas is credited with pioneering

252-418: A stressed member engine. During early testing of the 1983 Kawasaki GPZ900R , twin downtubes were included, creating a full cradle, but the downtubes were found to carry little load, so they were removed, relying entirely on the combination of the steel backbone and engine for chassis rigidity. BMW 's R1100 series twins of 1994 relieved the frame of stress entirely, with the engine carrying the total load from

288-424: A strong, lightweight structure that simplifies placement of engine and components, and gives good access for maintenance. Although construction of a trellis frame needs a more complicated process than, say, an alloy beam frame, it requires only a simple jig and a competent welder. No heavy capital outlay is required, so a trellis frame is ideal for a model that may be made in relatively small numbers. For this reason,

324-429: Is pressed or stamped from sheet metal to form a car-type semi- monocoque . One of the earliest examples was the 965cc motorcycle produced by Louis Janoir in 1920, which used pressed steel for the frame, rear swinging arm, and the front forks. The frame may be entirely pressed (Ariel Arrow), or may have just a pressed aft section connected to the steering head by a conventional steel tubular spine (Honda Super Cub). Both

360-437: Is a motorcycle 's core structure. It supports the engine, provides a location for the steering and rear suspension , and supports the rider and any passenger or luggage. Also attached to the frame are the fuel tank and battery. At the front of the frame is found the steering head tube that holds the pivoting front fork , while at the rear there is a pivot point for the swingarm suspension motion. Some motorcycles include

396-446: Is common to have a loadmaster as a part of the crew; their responsibilities include calculating accurate load information for center of gravity calculations, and ensuring cargo is properly secured to prevent its shifting. In large aircraft and ships, multiple fuel tanks and pumps are often used, so that as fuel is consumed, the remaining fuel can be positioned to keep the vehicle balanced, and to reduce stability problems associated with

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432-553: Is no single ideal frame design, and designers must make an informed decision of the optimum choice. In Europe and the USA, steel tubing was the default material until recent times. All the major manufacturers (AJS, Ariel, BSA, Matchless, Norton, Sunbeam, Triumph, Velocette, BMW, DKW, Ducati, Moto-Guzzi, Harley-Davidson and Indian) used steel tubing. Unlike the development seen in bicycle frames where tubular steel frames were succeeded by frames welded out of round or ovalized aluminium tubing,

468-416: Is suspended from a single spine. Spine could be a solid structure. The motorcycle engine is held in a single cradle with a single spine. Examples The motorcycle engine is held in a double cradle with a single spine and single downtube. The motorcycle engine is held in place within a pair of separate cradles. The Norton Featherbed frame was the classic example, but many "duplex" frames actually have

504-411: Is written in the form x / y , where x is the percentage of weight in the front, and y is the percentage in the back. In a vehicle which relies on gravity in some way, weight distribution directly affects a variety of vehicle characteristics, including handling , acceleration , traction , and component life. For this reason weight distribution varies with the vehicle's intended usage. For example,

540-486: The Aero-D One, featuring a composite monocoque chassis that weighed only 12 kg (26 lb). An aluminium monocoque frame was used for the first time on a mass-produced motorcycle from 2000 on Kawasaki's ZX-12R , their flagship production sportbike aimed at being the fastest production motorcycle . It was described by Cycle World in 2000 as a "monocoque backbone...a single large diameter beam" and "Fabricated from

576-458: The FIM award for the best manufacturer motocross sidecar 2007. Sidecarcross is carried out in the same way as regular motocross on broadly similar tracks. Just as with road outfits , the handling of sidecars is very different from solos, as the driver cannot lean the outfit in the turns to counter the centripetal forces . Instead, to ensure the outfit does not flip over, the passenger must lean out from

612-525: The Super Cub and the Arrow also have pressed steel forks, instead of conventional telescopic forks . More common in the car world, a monocoque frame comprises a structure where loads are supported through its external skin. On motorcycles they are used almost exclusively on racing motorcycles. French industrialist and engineer Georges Roy attempted in the 1920s to improve on the bicycle-inspired motorcycle frames of

648-579: The aluminium in motorcycle frames is almost exclusively welded in more angular forms, and often forming a monocoque frame. In 1983, Armstrong motorcycles produced a 250cc Grand Prix motorcycle using a revolutionary carbon fiber frame. Following the technology being used by the Formula One industry, Armstrong designers Mike Eatough and Barry Hart created the first motorcycle using a carbon fiber frame to compete in Grand Prix racing. The motorcycle engine

684-411: The bolt-on footboards for mechanical access. A monocoque-framed motorcycle was developed by Spanish manufacturer Ossa for the 1967 Grand Prix motorcycle racing season . Although the single-cylinder Ossa had 20 horsepower (15 kW) less than its rivals, it was 45 pounds (20 kg) lighter and its monocoque frame was much stiffer than conventional motorcycle frames, giving it superior agility on

720-482: The day, which lacked rigidity. This limited their handling and therefore performance. He applied for a patent in 1926, and at the 1929 Paris Automotive Show unveiled his new motorcycle, the Art-Deco styled 1930 Majestic. Its new type of monocoque body solved the problems he had addressed, and along with better rigidity it did double-duty, as frame and bodywork provided some protection from the elements. Strictly considered, it

756-639: The engine as a load-bearing stressed member; while some other bikes do not use a single frame, but instead have a front and a rear subframe attached to the engine. In the early days, motorcycles were little more than motorised bicycles , and consequently frames were tubular steel . While the use of steel tubing is still common, in modern times other materials, such as titanium , aluminium , magnesium , and carbon-fibre , along with composites of these materials, are now used. As different motorcycles have varying design parameters (such as cost, complexity, weight distribution , stiffness, power output and speed), there

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792-584: The engine, wheels, plastics, and other components from commonly available large-bore motocross bikes such as the Honda CR500, Kawasaki KX500, and large KTMs. There are also specialised "monster-size" 2-stroke engines such as the MTH 630, and 700cc Zabel which are made just for sidecar motocross racing. The Zabel and MTH are currently the top engines in the World Championship. HOCOB manufacturer of VMC chassis won

828-477: The frame is more properly called a "semi-monocoque". An example is Peter Williams' semi-monocoque Norton racer. A trellis frame connects the steering head to the swingarm pivot as directly as possible using metal tube arranged in triangulated reinforcement. Using lattice girder principles, a trellis frame is typically constructed of round or oval section metal tubular segments that are welded or brazed together. A well-designed trellis frame should provide

864-406: The frame, as a flexible frame acts as a spring to absorb some loads. In the 21st century, advances like high power engines driving high traction tires, and better-performing suspension components, especially forks, led to a situation where designs with increased overall frame stiffness were made available to consumers. Analysts differ on whether infinite lateral stiffness is desirable, or whether

900-401: The frame. It also becomes possible to mount the swingarm directly to the engine rather than the frame, avoiding the need for frame members extending downward to the swingarm pivot. By increasing the number of mounting points between the engine and frame, vibrations and stress can be better dissipated in the frame, typically creating a triangle between the swingarm in the rear, the cylinder head at

936-523: The front Telelever fork to the rear Monolever . Frame stiffness is a problem for motorcycle designers, as it was for the bicycle frames that motorcycles are descendants of. Modifying the stiffness of a factory-produced frame can be undertaken to improve handling characteristics. This is often done by triangulating the factory frame. Triangulation is a technique used in many engineering applications to stiffen structures. However doing so can also have undesirable effects if it overloads other parts of

972-529: The left, and European ones are on the right. Once riders are used to one arrangement, they seem reluctant to adapt the other layout. Many sidecar outfits (particularly the heavier ones) have leading link swingarm front suspension , as conventional telescopic forks are less capable of absorbing the stresses incurred. Several sidecar manufacturers (for example VMC , Bastech and EML ) in Europe make special chassis, usually with corresponding shocks, except for

1008-433: The load between the engine and frame reduces the overall weight of the motorcycle. Stressed member engines were pioneered at least as early as the 1916 Harley-Davidson 8-valve racer, and incorporated in the production Harley-Davidson Model W by 1919. This was called a keystone, or diamond, frame. The 1946 Vincent Series B Rapide was designed with an advanced chassis, termed a "tour de force for its day," that included

1044-413: The modern, aluminum perimeter frame chassis now used on many modern racing and production motorcycles. In 1982, Cobas developed a stronger and lighter aluminum twin-beam chassis to replace the steel backbone frames. The technology was copied by major motorcycle manufacturers and by the 1990s, all the major racing teams in Grand Prix competition used the aluminum frame design pioneered by Cobas. The frame

1080-463: The racetrack. Ossa won four Grands Prix races with the monocoque bike before their rider died after a crash during the 250 cc event at the 1970 Isle of Man TT , causing the Ossa factory to withdraw from Grand Prix competition. Notable designers such as Eric Offenstadt and Dan Hanebrink created unique monocoque designs for racing in the early 1970s. The F750 event at the 1973 Isle of Man TT races

1116-422: The rest of the machine. This strategy means the engine contributes little to frame stiffness, and absorbing rather than dissipating vibration can lead to stress damage to the frame, exhaust pipes, and other parts. Instead, if the engine is rigidly mounted to the frame, vibrations pass to and are dissipated via the whole frame, and the rider. Rigid mounting allows the engine to contribute to the overall stiffness of

Sidecarcross - Misplaced Pages Continue

1152-438: The sidecar as much as possible in corners. The passenger (sometimes known as the "monkey") moves his whole body around continuously, and plays a much more physical role than the sedentary driver. One of the most important aspects of sidecar racing is teamwork; the world's top sidecar teams have been racing together for many years. A World Championship is held over several rounds at top motocross venues throughout Europe, with

1188-415: The top and the lower crankcase area at the front. If a rigidly mounted engine not only contributes to, but is critical to, the stiffness of the frame, and is an integral part of closing the triangle or trellis structure that transfers force from the headstock to the swingarm, to the point that without the engine the frame would be deformed, the engine is called a stressed member , or a lifted engine . Sharing

1224-501: The trellis frame has found favour with European manufacturers, and Ducati in particular. Some motorcycles, such as the Yamaha TRX850 , have hybrid frames that employ alloy castings at the swingarm pivot area. Another variation is to suspend the engine from a trellis frame, but have the swingarm pivot cast into the rear of the engine. For rider comfort, a motorcycle's engine can be mounted on rubber bushings to isolate vibration from

1260-437: Was more of a semi-monocoque, as it used a box-section, pressed-steel frame with twin side rails riveted together via crossmembers, along with floor pans and rear and front bulkheads. A Piatti light scooter was produced in the 1950s using a monocoque hollow shell of sheet-steel pressings welded together, into which the engine and transmission were installed from underneath. The machine could be tipped onto its side, resting on

1296-505: Was won by Peter Williams on the monocoque-framed John Player Special that he helped to design based on Norton Commando . Honda also experimented with the NR500 , a monocoque Grand Prix racing motorcycle in 1979 . The bike had other innovative features, including an engine with oval shaped cylinders, and eventually succumbed to the problems associated with attempting to develop too many new technologies at once. In 1987 John Britten developed

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