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.
A two-wheel drive vehicle has two driven wheels, typically both at the front or back, while a four-wheel drive has four.
A steering wheel is a wheel that turns to change the direction of a vehicle. A trailer wheel is one that is neither a drive wheel, nor a steer wheel. Front-wheel drive vehicles typically have the rear wheels as trailer wheels.
A rare example of front wheel drive was the Opperman Motocart. This slow-speed agricultural and light freight vehicle was a tricycle with the front wheel carrying a large tractor tyre. The wheel was powered by a small single cylinder Douglas engine carried on the front mono fork that formed the steering gear.
See also Front-engine, front-wheel drive layout.
It was a common layout used in automobiles throughout the 20th century. At this time, FWD designs were not practical due to complexity (in FWD, engine power and steering must both be combined in the front axle).
For vehicles that have partial four-wheel drive, the term two-wheel drive refers to the mode when four-wheel drive is deactivated and torque is applied to only two wheels.
Four-wheel drive is common in because powering all four wheels provides better control on loose and slippery surfaces. Four-wheel drive manufacturers have different systems such as "High Range 4WD" and "Low Range 4WD". These systems may provide added features such as a varying of torque distribution between axles or varying gear ratios.
Common terms for this configuration include four-wheel drive, 4WD, 4x4 (pronounced "four-by-four"), integral, and all-wheel drive (AWD).
The Oshkosh M1074 and M1075 prime mover units in the U.S. Army's Palletized Load System (PLS), the U.S. Marine's 10x10 Oshkosh Logistic Vehicle System Replacement (LVSR), and the Tatra T816 10×10 cargo carrier are examples of ten-wheel drive vehicles.
10x10's are not as common as Four-wheel drive, Six-wheel drive and 8×8's.
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