Four wheel drive (4X4) has been around for a while and is extremely useful on rough terrain and off-road driving in general. The term 4 wheel drive means that the power is distributed evenly among the four wheels, while a normal car would either have front or rear wheel drive, with the other two wheels having no power source. Each type has its own characteristics, and with rear wheel drive, the front wheels are effectively being pushed along, while front wheel drive cars are pulling the rear wheels. Four wheel drive is much more efficient in wet and muddy conditions on the road, and once you get off the road, 4 wheel drive is in a class of its own.
Four by Four
Many off road vehicles and SUVs have 4X4 systems, and with modern vehicles, this can be turned on or off electronically. This allows the driver to select 2 or 4 wheel drive, and in normal driving conditions, 2 wheel drive is more economical and saves unnecessary wear on transmission parts. The 4X4 system is not entirely faultless, as the power that is distributed to each wheel is equal, and when you are in a turn, the outside wheels are turning faster than the inner wheels, but with four wheel drive, this causes a loss of traction, something you do not want to happen in any situation. 4X4 suspension is important and should be suitable for the type of terrain the vehicle will encounter.
All Wheel Drive
AWD is a more refined version of the traditional 4X4, as each wheel is driven, but not all at the same speed. When the vehicle is turning, this allows the inner wheels to rotate at a slower rate than the outer units, and this enables four wheel traction and much better control. Suspension is critical for AWD, and if you are in Western Australia, and would like to beef up your truck a little, try 4×4 suspension by West Coast Suspensions, who also have an impressive range of accessories at affordable prices. AWD can be turned on and off, which can be done manually, usually with a small lever near the gearshift, or electronically, via a switch. As a rule, the driver would leave the car in AWD, as this distributes the power to each wheel as it is needed, and this extra efficiency makes it more economical, as the engine requires less fuel.
There is no doubt that AWD gives the vehicle more stability, especially in wet and slippery conditions. There are several power changes (engineered gearing that split power), with a central unit halfway down the centre differential, and smaller ones that feed each wheel. The downside to AWD is that it doesn’t perform well on rough terrain at slow speed, which is why most off road vehicles are fitted with 4WD. Many of the Hi-end cars we drive today would have AWD as standard, and the system would offer the driver an added level of control.
Both 4X4 and AWD are very efficient systems and enable the vehicle to encounter a range of surfaces that a traditional 2 wheel drive would not. AWD can be regarded as a further development to four wheel drive, and although they are slightly different, both improve traction, and therefore safety.