Two-wheel-drive (2WD) denotes vehicles
with a drivetrain
that allows two wheel
s to be driven, and receive power
from the engine
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
, 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
, 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
and Christini. Manufacturers who are working or have worked on a prototype include ZID
, and Nissan
Two-wheel-drive with sidecars
For three-wheeled vehicles such as motorcycle
s with sidecar
s, 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
A brief history of 2x2 motorcyclesKTM shows a new all-wheel-drive motorcycle under developmentChristini All Wheel Drive MotorcyclesThe Dryvtech 2x2x2 Experimental, a 2x2 motorcycle with two-wheel steering