The automotive world can be as confusing as it is exciting. On one end you have great cars, and high speeds and on another you have lots of abbreviations and parts that just make cars hard to understand.
On the top of the list of abbreviations and short forms that cause headache is 4WD, AWD and 2WD. You have probably seen or heard these before and you might have used some or all of these without really knowing what they are. If you are in this category then this is for you, we are stripping these terms down to the bone.
To understand how 4WD, AWD and 2WD work, you need to first understand how a car engine moves the wheels of the car. Without getting too technical, when you step on the accelerator pedal, the engine creates a turning motion called torque.
Torque is the force that is transferred to the wheels and makes them spin and in turn moves the car. So, the 4WD, AWD and 2WD settings are dependent basically on Torque.
2WD – Two Wheel Drive
Majority of the cars on the road today are made with 2 wheel drive. This means that when the engine produces torque, the power will always be transferred to two wheels only.
Either the front two wheels (Front wheel drive) or the hind two wheels (Rear wheel Drive) will propel the car forward or backward. The other two wheels that are not being powered are there to support the rest of the car because a car needs 4 wheels and not two.
2WD is a good setting for normal or basic driving conditions. It is simple and easy, but comes with one draw back which is a lack of traction.
Traction is the gripping force that enables a car to stay in the ground as it runs. More traction means more stability for a car. 2WD cars have okay traction and it serves them well until they get on a slippery road, get stuck in some mud or run on a rocky surface then things get tricky and there is need for some more traction.
You should know, if you don’t already that almost all sedans, station wagons, mini vans and SUVs have 2WD by default. So, unless a car is specifically labelled AWD or full time 4WD, it has 2WD.
4WD – Four Wheel Drive
4WD drive is best suited for off road driving and those times when you get stuck. While with 2WD, engine power is transferred to 2 wheels only, with 4WD, the power is transferred to all the 4 wheels at the same time (4×4) in a 50:50 ratio. Meaning 50% to the front wheels and 50% in the hind wheels.
The purpose of 4WD is to increase traction not engine power. It does not make the engine stronger, it just redistributes the engine power better and gives the car more traction.
The more traction a car has, the better the grip and the easier it can navigate uneven terrain. One should note that 4WD cars have 2WD by default. It is after you engage the 4WD system that all the 4 wheels receive engine power.
When you are looking to engage 4WD, the gear levers usually have the labels 4H (High) and 4L (Low) .
4WD High is used when you are driving at speeds above 15mph (25kph) and you need to have some traction. This can be over a slippery road or a really stony murrum road where you feel the car could easily get out of control as you drive, but you are not moving very slowly.
If the road to your village has puddles and mud patches here and there, this is the setting you will need as you can move relatively fast while still enjoying the benefits of 4WD. It is important to note that you should never drive at speeds over 80kph in any 4WD setting otherwise you could damage the car.
4WD Low is used when you are driving below speeds of 25 kph or in tight spots like when you are stuck in mud. It is also vital when driving over rocky terrain, ascending a steep slope or if you are driving over deep sand.
The Low setting has the most traction and will give your car the most grip as all the 4 wheels will be moving as one to get you out of your hard spot.
AWD – All Wheel Drive
Like the term suggests AWD is where all the wheels are in motion, receiving power from the engine at the same time all the time. The difference between AWD and 4WD is that 4WD will transfer power to all the wheels only when you engage it, while AWD transfers power to all the wheels at all times. AWD cars are designed to run that way from the production line and therefore do not require the driver to engage the setting.
AWD cars have more traction than 2WD and are usually better at acceleration because all the 4 wheels receive power from the engine. You might see sometimes on a slippery road where some cars are sliding while some others that are not 4WD cars are cruising with ease, that is most probably because the latter cars have AWD. Many manufacturers of sports cars and family vans prefer AWD to 2WD because of the increased traction which provides more stability.
Some of the cars that commonly have AWD include Subaru Legacy, Nissan Juke, Mitsubishi Lancer and even the Lamborghini Aventador.
Read: 2000 Subaru Forester T25 (STi) Review
