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All-wheel drive and four-wheel drive - it’s the same thing, right?
Yes and no.
In simple terms, the difference between all-wheel drive (AWD) and four-wheel drive (4WD, FWD or 4x4) can be defined by the purpose of the vehicle, as both examples can drive all four wheels of any vehicle.
While there are exceptions to this rule, AWD vehicles tend to be more focused on providing on-road traction, either for traction in slippery conditions or more performance. Examples of this are the Subaru WRX and any Audi ‘quattro’ model.
In contrast, a 4WD vehicle typically is more focused on off-road capability and will tend to have a low range gearbox for improved low speed traction. Some examples of this are large SUVs like the Toyota LandCruiser and Nissan Patrol and many modern 4x4 utes.
But there’s a lot more to the two different types of drivetrains, which we’ll now dive into in detail to give you a clearer understanding of the benefits and differences so you can decide what is best for your needs.
As mentioned above, the biggest differences between the pair tend to be separated as much by intent as technical differences. But there are some other key distinctions between the two in how they operate and there is becoming an increasing gap between the two thanks to the introduction of electric-AWD options that complicate matters further.
To keep it relatively simple and avoid a technical dissertation, AWD systems like we’re familiar with from Audi and Subaru, use either two or three differentials and the car’s on-board computer determines where traction is needed and automatically distributes it.
A 4WD system can also use two or three diffs but tends to split the power evenly between the front and rear axles, via the transfer case, and maintains a steady split between the two rather than varying drive.
There are two popular forms of 4WD - full-time (or permanent) and part-time - but both perform a similar function but with some key differences.
Full-time 4x4 requires three differentials - front, centre and rear - whereas a part-time set-up only has the front and rear diffs.
As the name implies, a full-time 4WD or FWD system is always sending drive to all four wheels, so it needs the centre diff to allow different speeds to each axle.
In contrast, a part-time system uses a transfer case, which is able to disconnect the front axle when you’re not driving on loose surfaces, which allows the front wheels to spin freely which improves how the far handles and reduces fuel economy.
But, when you go off-road, you can engage the front axle via the transfer case for improved traction.
Both versions typically offer you the choice between ‘high range’ and ‘low range’ which you can shift into depending on the road conditions.
For higher speed off-road running - say, a gravel road or sandy track, using ‘high range’ or ‘4H’ is best as it allows the wheels to spin faster.
Whereas, ‘low range’ or ‘4L’ is better for slower speeds as the wheels don’t turn as fast but this helps in really slippery conditions by providing superior traction, so this is what you’d use to crawl over rocks or navigate a particularly gnarly stretch of terrain.
While an all-wheel drive system does send drive to all four wheels, it has some fundamental differences to a 4WD - both full-time 4x4 and part-time FWD. The most obvious one is the lack of a transfer case and instead drive is directed to each wheel via either a limited slip differential or an electronically-controlled clutch.
This is what allows an AWD system to direct the torque to where it is needed, while allowing for the wheels on each axle to turn at different speeds in corner to turn corners.
None of this is to suggest AWD vehicles aren’t off-road capable - far from it. Many AWD vehicles are very capable of driving on dirty, muddy roads, such as the likes of the Subaru Crosstrek and Forester, and many other modern SUVs.
But AWD has also become a popular choice for performance cars as manufacturers extract huge amounts of power and torque and two-wheel drive vehicles struggle to transfer so much grunt to the road.
It’s why cars like the BMW M5, Mercedes-AMG C63 and more use AWD, because the addition of the extra differential allows for all that extra grunt to be divided between each wheel in a more manageable way.
Electric all-wheel drive (eAWD) is a newcomer to this segment, with many brands using either electric motors mounted on each axle or a combination of internal combustion and electric power.
In this instance an internal combustion engine is used to power one axle but instead of dealing with the complexity of extra diffs and driveshafts, they have discovered that you can more simply add an electric motor to the other axle to provide AWD traction.
An example of this is the new Toyota Corolla Cross, while a showcase of an all-electric AWD set-up is the Tesla Model Y Dual Motor or Audi e-tron.
However, vehicles such as the Rivian R1T and GMC Hummer are using eAWD for better off-road performance because they feature four electric motors, one for each wheel, so the carmakers can program each individual motor to deliver optimum traction on slippery surfaces.
It’s actually pretty simple, you just need to ask what sort of driving you intend to do?
Are you looking for something that can take you deep into the bush? Or just something that can help you when it rains? Or are you looking for something high-performance that requires extra traction?
If your goal is to tackle some really rugged off-road, look at 4WD options with low range as they’ll give you the best capability on slippery surfaces. But if your priority is urban driving with some occasional loose surface trips, then an AWD model may be all you need.
The biggest difference is probably to decide between light-duty vs heavy-duty off-roading - with AWD best for the former and 4WD better for the latter.
Or to put it another way, if you’re planning one or two weekend off-road adventures per year, AWD will most likely suffice, but if you’re planning regular trips off sealed roads or that big around-Australia trip you’ll want to look at either a full-time 4x4 or part-time 4WD.
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