What is the first thing that comes to mind when you hear the words "4x4"? A big powerful machine, capable of driving over large obstacles and through rough terrains? On the one hand, yes, that might be true. But these days, even some of the fanciest utility vehicles or sports utility vehicles are also classified as 4x4's.

So what exactly does the abbreviation 4x4 refer to? Quite simply put, the first figure is the total number of wheels on the vehicle and the second is the number of powered wheels. The four-wheeled vehicle has a drive-train that allows all four wheels to receive torque from the engine simultaneously. Experts say powering all four wheels provides better control than normal road cars on many surfaces.

But there is not necessarily power on all four wheels all the time.

Some four wheel drive vehicles allow the driver to manually switch between two-wheel drive mode for everyday driving and four-wheel drive mode for low traction conditions such as ice, mud, snow, slippery surfaces, or loose gravel. 4x4's are well known for their great handling abilities on surfaces that are less than ideal and require extra grip to travel on safely.

Part time four wheel drive systems are mechanically simpler, cheaper, and tougher than all-wheel drive systems, and inherently better at making use of available traction. These systems are equipped with a gear reduction setting that multiplies torque for greater power at lower speeds, a vital feature for vehicles that will see much off road use. However, this system lacks a centre differential, and as such, a part time system can only be used in low traction situations where the wheels have the ability to slip as needed.

Some four wheel drive systems are extremely advanced and can automatically redistribute power to the wheels that do have grip should a wheel end-up in a hole, thus helping you get out of trouble quickly. If you were in this same scenario with a front wheel drive car, you will only have one powered wheel left which would not necessarily be as effective. However, in order to make the most of your 4x4 safely, it is advisable to go for training.