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If the differences between four-wheel, all-wheel and rear-wheel drive all sound a little confusing, then you aren’t alone. With the way car manufacturers throw around terminology and classifications these days, it’s enough to stump even the most experienced of motorists.
To help clear things up, we’ll define each category in greater detail, go into their pros and cons, and – if you’re in the market for a new car – explore what kind of motorist each type is suited for.
Before we go any further, it’s worth explaining something that’ll be popping up a fair bit throughout this article: the drivetrain.
Made up of the transmission, the driveshaft, the axles and your car’s wheels, the drivetrain is essentially what makes your car ‘go’. These parts all interact with the engine to move parts of the vehicle that, literally, put the wheels in motion.
Once found mainly in large trucks and SUVs, when you picture a 4WD you picture a truck with high ground clearance, enormous tyres, tow hooks and a shielded underbody. But 4WD engineering has seen its fair share of evolution since the heady of days of its rough-and-ready origins. Although you’ll find them in plenty of off-road models, 4WD systems are used in a wide variety of other vehicles nowadays too.
4WD drivetrains deliver torque (or rotational force) through a series of front, rear and centre differentials to all four of a vehicle’s wheels. This increases traction and allows them to take on more rugged terrain with ease. And since this mode is optional, you can just as easily drive around using the usual 2WD system instead.
Many 4WD systems also have low and high ranges that can be selected by the driver by an electronic switch or a floor-mounted lever. The low setting provides maximum traction on off-road environments, while the high setting is the default configuration, allowing you to take on conditions like snow, ice and gravel with ease.
If it’s traction and power you’re after, then 4WDs have both in spades. Their other advantages include:
Improved traction and control when both sets of wheels are engaged
Additional weight means greater grip on the road, especially when accelerating
Stronger performance when towing
The added benefits of a 2WD system with 4WD at the push of a button
4WD systems aren’t without their drawbacks. Keep in mind the following disadvantages if you’re thinking of purchasing one:
The extra parts and technology needed to make 4WDs work make them pricier to purchase and maintain
Their power and weight mean such systems guzzle up fuel, so they’re less efficient than their 2WD counterparts
The increased power and traction might lead to overconfidence in some drivers. Combined with the increased braking distance, this may lead to accidents and collisions as a result
For off-road purists and needing the increased power to climb steep hills and take on rocky terrains, or anyone that must navigate tricky driving conditions every day, it doesn’t get much better than a 4WD.
For everyone else, 4WD is a bit of a luxury. If you’re just driving to and from work, you’re better off opting for something else.
AWDs, as their name suggests, power both the front and rear wheels at the same time, all the time. AWD systems differ from 4WDs in that they require no driver selection to drive all four wheels.
In what are known as part-time AWD systems, sensors are placed on each wheel of the car to accurately monitor traction, wheel speed and other conditions. Using this data, the AWD system decides where the power is sent, and the vehicle can safely navigate the conditions of the road by itself.
In full-time AWDs, on the other hand, their front and rear axles are driven all the time. On dry roads, this allows the vehicle to handle better and drive at full power, while in slippery conditions, it provides greater traction and safer, more confident performance.
What makes AWDs stand out from other drivetrains? Here’s what this modern innovation can offer to motorists:
No decisions are needed to engage the system. With AWDs, either all the wheels are being driven all the time, or sensors within the system decide to activate them for you
Should one or two wheels lose traction in slippery conditions, AWD systems can distribute traction quickly to the necessary wheels, keeping things steady and stable on wet or icy roads
AWD allows for sportier handling and traction in a range of different car types thanks to intelligent torque vectoring
In certain regards, the same disadvantages of 4WDs also apply to AWDs, including the following:
Costly to produce and manufacture, which makes them more expensive than their two-wheel-drive counterparts
AWDs are beset by the same false sense of security and overconfidence that affects 4WDs
Because power is being sent to all four wheels, AWDs tend to see large drop-offs in terms of their fuel efficiency
For true-off roaders, AWDs are considered the lesser choice. For those who prefer to take on rockier terrains and want to engage four-wheel drive for themselves, 4WDs are still the go-to.
With that said, modern AWD systems are becoming more and more capable, which has gone a long way to changing this purist perception. And because it can be found in cars of all sizes, AWDs provide a greater range of vehicles to choose from.
For those looking for greater traction in normal winter conditions (as well as light off-roading) with fewer compromises in ride and fuel economy on dry roads, an AWD could well be the right choice.
In a RWD car, the engine powers the rear wheels only. The oldest form of drivetrain, RWD is becoming increasingly rare in the motoring world, despite it being the preferred setup of driving enthusiasts across the globe.
Since the rear wheels are powered, the car is also ‘pushed’ from behind, rather than being ‘pulled’ from the front. It’s because of this that certain motorists feel RWDs offer a greater driving experience.
So, what else can we factor into RWD’s supposed greater driving experience? Their myriad advantages also include:
Rear-wheel drive improves handling due to “load transfer” in acceleration and more even weight distribution in dry conditions
With fewer parts packed into a small space, rear-wheel drive tends to be cheaper to maintain.
As opposed to front-wheel drive vehicles, which have a tendency to veer to the right or left under acceleration, RWD’s don’t experience “torque steer”
Since the wheels doing the pulling are located closer to the load, towing large loads is much easier
Likewise, steering is much easier since the back wheels are responsible for providing the power
Since the undercarriage and rear of the car houses the transmission and driveshaft, RWD vehicles have less interior space
The setup of RWD vehicles means they’re difficult to manoeuvre in wet and snowy conditions
Even though the cost to maintain a RWD is cheaper than a front-wheel-drive car, the former is more expensive to purchase due to how much it costs to produce the axle of a RWD system
If you live in an area that’s prone to snow and other poor weather conditions, a RWD may not be your best bet. However, if you’re living in an area with little inclement weather, then a RWD is most definitely a sensible option.
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