Many of us might only be dimly aware of how many wheels ‘drive’ our cars – i.e., how many of the four wheels on the vehicle are directly powered by an engine or a propulsion motor – but, for the majority of machines, the answer is two.
On smaller, lighter, more affordable vehicles, the driven wheels will generally be the fronts. For larger, performance-oriented and luxury vehicles, the driven wheels tend to be the rears.
However, there’s a proportion of cars on which all four wheels receive power from the engine or motor. Typically, these four-wheel-drive (4WD) vehicles were usually SUVs, pick-up trucks or 4x4s, like the Land Rover Defender, Toyota Land Cruiser and Ford Ranger, because these were all designed to actually go off-road – and that’s where 4WD comes into its own.
Yet some manufacturers refer to 4WD as all-wheel drive (AWD), so what we’re going to look at here is whether there’s a difference between the two, and whether you even need either of them.
Is there any difference between AWD and 4WD?
So, as we’ve already said, AWD is all-wheel drive and 4WD is four-wheel drive. This might sound like the same thing, and it is, but historically there was a bit of a difference between them.
With 4WD, for instance, it was often a heavier-duty system with locking differentials, and sometimes selectable low- and high-ratio gearboxes. This sounds very technical, so we’ll simply say that 4WD is ordinarily used for the very toughest of vehicles that are designed to go a long way into the wilderness – something like a Mercedes G-Wagen or Jeep Wrangler, for instance.
AWD, however, normally refers to a lighter, simpler system that works automatically, and it was in the past used only for road-biased vehicles. Something like a Volkswagen Golf R, for instance, uses what was once known as an AWD set-up. It can run in part-time two-wheel drive if needed, to save fuel, and would automatically switch to all-wheel drive, as and when its control system decided that torque was required at a given tyre.
The problem is that, in recent years, manufacturers tend to have used the two terms interchangeably, so some simpler systems become 4WD and more advanced hardware AWD. A fine example of the latter is Subaru, a company wedded to its idea of symmetrical AWD, which is a permanent set-up that provides excellent abilities on the car. In fairness to Subaru, it has used the term symmetrical AWD, rather than 4WD, for years, but it still causes confusion.
In short, either AWD or 4WD means all the wheels on your car can be powered by the engine and can work to propel the vehicle forward.
Right, but do I need either four- or all-wheel drive?
It is, as it has ever been, very useful for vehicles which actually go off-road from time to time. Of course, either AWD or 4WD are not going to get you very far if you’re on sports tyres and you don’t have a lot of ground clearance – a Toyota GR Yaris, for instance, has a four-wheel-drive system, but you wouldn’t exactly take it up the roughest of trails because it’s a small hatchback.
But big SUVs, pick-up trucks and luxury 4x4s will all use AWD or 4WD, and they will normally be fitted with the sorts of tyres that can take advantage of the set-up as standard.
Another area of benefit is towing. Four-wheel-drive machines are excellent tow-cars, due to their traction properties. Again, vehicle weight is a benefit so SUVs, 4x4s and pick-ups are the preferred modus operandi here, but if there’s a big estate car with AWD – some models of the Skoda Superb Combi, for example, had AWD – then they would make a solid alternative for towing caravans or smaller horseboxes on-road.
AWD has also been used in performance applications, where flowing a lot of power through only one axle would make for an unruly driving experience. Great examples of this are ‘hyper hatches’, like the Audi RS 3, Mercedes-AMG A 45 S and Ford Focus RS, which would be notably compromised if they were only front- or rear- driven.
Finally, even if you stay permanently on tarmacked roads when driving, if you live in a remote part of the country where the winter weather is frequently very bad and the roads not properly looked after, then AWD or 4WD would be a help for getting around on essential errands. Again, though, all-corners traction is only going to help you in these instances if you have the right tyres fitted – anything summer-oriented won’t be much use at all when the road conditions turn treacherous.
For everyone else, who predominantly drive in towns and cities, and live in parts of the country where the roads are looked after, then two-wheel drive will be fine – one of the disadvantages of AWD/4WD is that it can make vehicles it is fitted to rather fuel-inefficient, for example.