RPMGO answers: What's the difference between four-wheel drive (4×4) and all-wheel drive (AWD) ? | Rpmgo.com

Hello and welcome to another edition of RPMGO answers, where we take a stab at explaining in more layman’s terms various automotive debates or technologies.

We’ve already covered a few basic things, and now we’re treating something a bit more in depth: What’s the difference between four-wheel drive (4WD) and all-wheel drive (AWD) vehicles?

Now you may be inclined to say that there isn’t any difference, but this is due to marketing terms and various PR work from carmakers, as there are quite a few things setting the two systems apart. If you want to find out what they are, hit the jump.

There are various benefits and disadvantages between front-wheel drive and rear-wheel drive cars, which we explained in the last RPMGO answers feature. As such, plenty of carmakers have started offering four-wheel drive options to their models, especially the ones which aim at offering a decent off-road experience.

Let’s start with four-wheel drive systems, commonly highlighted by the 4×4 badge, even though most AWD cars have the same number of wheels, 4, and the power of the engine is directed to them, hence the second 4. This type of system is split up in two segments: part time 4×4 and full 4×4.

The part time 4WD is aimed at people who want a good two-wheel drive car on the road, for everyday use, but also want something that can be used for off-road conditions, when all of the wheels need to receive power from the engine. Such vehicles have a special switch, or transfer case highlighted by a second gear shifter, with settings like 4WD Hi or 4WD Lo. This, like I’ve said, basically sends the power of the engine to all of the wheels, without any other intervention, making it ideal for extreme conditions like snow, mud or rocks. This however makes the vehicle extremely bad for on-road use, as it won’t go around corners very well, and the transfer case will be subjected to extreme stress in non-off-road use. This system is used on specific off-road vehicles, which are preferred by enthusiasts.

Full-time 4WD means that there is no switch, and that all four wheels are receiving power from the engine all the time, no matter the conditions. The transfer case in such models is specifically changed, meaning that it will resist on the road and off it, and also features the Hi and Lo settings, depending on the speed you’ll want to reach. This system increases safety and the handling of the vehicle in tricky conditions, but also impacts the fuel consumption. It is used commonly in many SUVs these days, combining the best of both worlds for drivers.

That was the 4WD system, now onto the AWD, which also has two variants: full and automatic, depending on the aim of the carmaker. Overall, AWD is also the most common these days.

The Full AWD system basically acts like the full-time 4WD, but lacks the Hi or Lo settings for the transfer case, essentially taking away any control the driver may have on the way the wheels receive power from the engine. Everything is done thanks to the many electronic systems, and is specifically configured to offer the safest ride, although it will hardly be able to do any type of serious off-roading. This type of system is commonly used in all sorts of vehicles, including sedans from Audi or Subaru.

Automatic AWD is basically a 2WD car, most commonly FWD, which only sends power to the other set of wheels when the computer decides it has to, most commonly in tough conditions, or when the other wheels are slipping. When the car is in such a situation, the rest of the wheels will add that extra stability, and get it out of the predicament, basically like a last safety measure. Improved fuel efficiency is also an added bonus for such a setup. Automatic AWD is mostly used in crossovers and so-called “soft-roaders”.

The basic difference between 4×4 and AWD vehicles is their target audience. The 4×4 models are basically made for people who want to be in control, and know what they’ll use the car for. AWD cars, on the other hand, offer a much safer alternative as the on-board computer controls all of the wheels, keeping the car in check, without affecting the driver all that much.

In the end, it depends on what type of consumer you are. Don’t forget though that no matter how many wheels are receiving power, it isn’t an excuse to push the car above its limits. We’ve seen big, tough SUVs get stuck in the snow or mud as easily as FWD sedans or RWD sportscars.

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