Try driving in a tight circle on dry pavement with four-wheel drive engaged and you'll both feel and hear an unnerving shudder as the driveline binds up. Sometimes the front tires will also hop and chirp. This binding stresses the driveline and will cause the tires to wear unevenly if four-wheel drive is regularly used on paved roads.
More important, using four-wheel drive on pavement can be dangerous, as the locked driveline can make turning difficult. On low-grip surfaces such as snow, ice, dirt, or mud, binding isn't a problem because the tires can slide freely over the surface to reconcile the locked driveshafts with the need for each tire to trace a unique arc.
Just as you can order a Miller Lite with a shot of tequila, it's possible to buy a vehicle with both an all-wheel-drive and a four-wheel-drive system. Optional in many modern full-size pickup trucks, these systems allow the driver to choose all-wheel drive with an Auto or 4Auto mode and four-wheel drive with the 4High setting.
These vehicles typically also include a rear-wheel-drive 2High mode and low-range 4Low mode. A Mercedes-Benz G-wagen, for instance, behaves like an all-wheel-drive vehicle until you lock its center differential, at which point it becomes a four-wheel-drive truck.
Auto manufacturers don't make it easy for buyers to decipher the technology underneath their vehicles. Many vehicles with Subaru's Symmetrical All-Wheel Drive actually split torque between the front and rear axle asymmetrically. Chevrolet brands its all-wheel-drive trucks as four-wheel drive, while four-wheel-drive models are four-by-fours. Ford also insists on using four-wheel drive to describe its many all-wheel-drive SUVs. One of the easiest ways to know if your vehicle has all-wheel drive or four-wheel drive is to crack open the owner's manual.
If it warns against activating the system on dry pavement, you have four-wheel drive. Barring that, the system is likely all-wheel drive. And if you're considering a new vehicle, you'll want to know these distinctions before you buy. Nor do all-wheel-drive systems from different manufacturers perform exactly alike, as illustrated by this video.
After getting stuck or losing control in slippery conditions, some drivers become convinced that they need a vehicle with AWD or 4WD. AWD and 4WD also aids traction, depending on the conditions, when towing a boat, caravan or float. This is evident when towing on wet or slippery roads, at a wet boat ramp or on unsealed roads designed for off-roading.
It is also handy when driving on sand. AWD or 4WD models generally cost more than equivalent two-wheel-drive models. Likewise if you live in an area that gets a lot of rainfall or snow. When it comes to towing a caravan, boat, horse float or bigger trailer, it is definitely recommended.
The Mazda CX-9 Touring drinks 8. This can add up over a year of filling up, so consider whether you really need the 4WD version. SUVs are big business in Australia and have overtaken traditional passenger sedans, wagons and hatchbacks as our favourite type of car.
But anyone choosing an SUV assuming it will have some off-road ability might be disappointed. In decades past, what we now know as SUVs were rugged four-wheel-drive wagons engineered and built with off-road driving in mind. SUVs of all sizes have taken over and a quick look at the small SUV segment shows that only a handful of variants are even offered with all-wheel drive — most are front-wheel drive only.
Many manufacturers including Ford, Holden, Isuzu, Mitsubishi and Toyota sell SUVs based on their respective 4x4 utes and all of them are built for off-road adventures. Alternatively, those very utes they are based on are also quite handy off road. This site will not function correctly without JavaScript enabled. Please enable JavaScript in your browser. In slippery situations where your two-wheel drive vehicle sits spinning its wheels, an AWD vehicle will likely get up and moving in quick order.
All-wheel drive is typically decision-free. No button to press or lever to pull. But AWD can be found in virtually any type of vehicle. Sometimes, AWD systems have a unique name cooked up by the marketing department. Though AWD systems may have different and sometimes-confusing names, they all work the same way: by providing power to all four wheels to enhance traction.
In many but not all cases, a 4WD or 4x4 system needs to be turned on when its services are needed. Where an AWD system is always driving all four wheels, many 4x4 systems need to be activated by the driver, typically by pressing a button, turning a dial, or pulling a lever. When the 4WD or 4x4 system is engaged, all four wheels are powered. When disengaged, the vehicle runs in two-wheel drive, typically rear-wheel drive.
Further, some 4x4 or 4WD systems always power all four wheels — as can be found on certain versions of the Jeep Grand Cherokee. The gist? End of the day, they all have the same goal: drive all four wheels for added traction.
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