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Two-wheel-drive (2WD) denotes vehicles with a drivetrain that allows two wheels to be driven, and receive power and torque from the engine, simultaneously. [1]
| | This article needs additional citations for verification .(December 2010) |
Two-wheel-drive (2WD) denotes vehicles with a drivetrain that allows two wheels to be driven, and receive power and torque from the engine, simultaneously. [1]
For four-wheeled vehicles (and by extension, vehicles with six, eight, or more wheels), this term is used to describe vehicles that are able to power at most two wheels, referred to as either front, or rear-wheel-drive. The term 4x2 is also used, to denote four total wheels with two being driven. Most road vehicles use a 2WD layout due to its lightweight and simplicity. Traction on the road is usually sufficient that the driving force can be reliably transmitted through only two wheels.
For vehicles that have part-time four-wheel drive, the term refers to the mode when 4WD is deactivated and power is applied to only two wheels.
For two-wheeled vehicles such as motorcycles and bicycles, the term is used to describe vehicles that can power the front as well as the back wheel. The term 2x2 is also used to denote two total wheels with both being driven. 2x2 vehicles are typically either mechanically driven, via a chain, belt, or shaft, or are hydraulic-driven. This scheme greatly improves offroad performance, but is quite complicated and requires more power to operate, thus most 2WD machines are either "exotic" bikes for enthusiasts or created with special uses in mind.
Manufacturers who have one in production include Rokon, Jeep, Tarus and Christini. Manufacturers who are working or have worked on a prototype include ZID, Suzuki, Yamaha, KTM, Honda, and Nissan.
For three-wheeled vehicles such as motorcycles with sidecars, the term is used to describe vehicles that can power the sidecar as well as the back wheel. Sidecar-drive vehicles are typically mechanically driven via a shaft and may or may not have a differential. This scheme greatly improves offroad performance, but is more complicated and requires more power to operate, thus most 2WD machines are vehicles created with special uses in mind such as trials or military use. The first use of the sidecar drive appears in 1928 with the apparent independent invention of Baughan in the UK, and Mokharov in the USSR.[ citation needed ]
An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type of axle is referred to as a spindle.
A sidecar is a one-wheeled device attached to the side of a motorcycle, scooter, or bicycle, making the whole a three-wheeled vehicle. A motorcycle with a sidecar is sometimes called a combination, an outfit, a rig or a hack.
Four-wheel drive, also called 4×4 or 4WD, refers to a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case providing an additional output drive shaft and, in many instances, additional gear ranges.
Quattro is the trademark used by the automotive brand Audi to indicate that all-wheel drive (AWD) technologies or systems are used on specific models of its automobiles.
In automotive design, a front-engine, front-wheel-drive (FWD) layout, or FF layout, places both the internal combustion engine and driven roadwheels at the front of the vehicle.
In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bumper. Although very common in transit buses and coaches due to the elimination of the drive shaft with low-floor buses, this layout has become increasingly rare in passenger cars.
Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-wheel drive vehicles feature a longitudinally-mounted engine at the front of the car.
A transfer case is a part of the drivetrain of four-wheel-drive, all-wheel-drive, and other multiple powered axle vehicles. The transfer case transfers power from the transmission to the front and rear axles by means of drive shafts. It also synchronizes the difference between the rotation of the front and rear wheels(only high-speed 4wd-Awd systems), and may contain one or more sets of low range gears for off-road use.
A locking differential is a mechanical component, commonly used in vehicles, designed to overcome the chief limitation of a standard open differential by essentially "locking" both wheels on an axle together as if on a common shaft. This forces both wheels to turn in unison, regardless of the traction available to either wheel individually.
A sprocket, sprocket-wheel or chainwheel is a profiled wheel with teeth that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which radial projections engage a chain passing over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth except for timing pulleys used with toothed belts.
A drive shaft, driveshaft, driving shaft, tailshaft, propeller shaft, or Cardan shaft is a component for transmitting mechanical power and torque and rotation, usually used to connect other components of a drivetrain that cannot be connected directly because of distance or the need to allow for relative movement between them.
A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers enough torque to the wheel to overcome stationary forces, resulting in the vehicle moving forwards or backwards.
In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, from front to back.
The Scott Sociable was an English automobile manufactured from 1921 to 1925 by the Scott Autocar Company of Bradford, Yorkshire, an offshoot of the Scott Motorcycle Company.
Super Select is the brand name of a four-wheel drive system produced by Mitsubishi Motors, used worldwide except for North America, where it was initially known as Active-Trac. It was first introduced in 1991 with the then-new second generation of the Mitsubishi Pajero.
Motorcycle components and systems for a motorcycle are engineered, manufactured, and assembled in order to produce motorcycle models with the desired performance, aesthetics, and cost. The key components of modern motorcycles are presented below.
Bicycle drivetrain systems are used to transmit power on bicycles, tricycles, quadracycles, unicycles, or other human-powered vehicles from the riders to the drive wheels. Most also include some type of a mechanism to convert speed and torque via gear ratios.
A drivetrain is the group of components that deliver mechanical power from the prime mover to the driven components. In automotive engineering, the drivetrain is the components of a motor vehicle that deliver power to the drive wheels. This excludes the engine or motor that generates the power. In marine applications, the drive shaft will drive a propeller, thruster, or waterjet rather than a drive axle, while the actual engine might be similar to an automotive engine. Other machinery, equipment and vehicles may also use a drivetrain to deliver power from the engine(s) to the driven components.
An all-wheel drive vehicle is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand.
This glossary of automotive terms is a list of definitions of terms and concepts related to automobiles, including their parts, operation, and manufacture, as well as automotive engineering, auto repair, and the automotive industry in general. For more specific terminology regarding the design and classification of various automobile styles, see Glossary of automotive design; for terms related to transportation by road, see Glossary of road transport terms; for competitive auto racing, see Glossary of motorsport terms.