All-Wheel Drive (AWD) vs Four-Wheel Drive (4WD): What's the Difference?
Learn about the difference between four-wheel drive and all-wheel drive to find out which one is right for you.
When it comes to confusing automotive terminology, the difference between four-wheel drive (4WD) and all-wheel drive (AWD) is one that can trip up even the savviest of car shoppers. Since cars generally only have four wheels, shouldn't 4WD and AWD mean the same thing?
The main difference between 4WD and AWD is that four-wheel drive is triggered manually by the driver to help navigate difficult terrain or uncertain weather, while all-wheel drive is an "always-there" performance feature that relies on sensor data to automatically adjust your wheels to provide better traction and handling.
Still not clear? Here's a little more detail on these two distinct technologies:
What Is Four-Wheel Drive?
In four-wheel drive vehicles, power can be directed to all wheels simultaneously, allowing each of them to have traction with the ground surface.
Usually associated with large trucks, SUVs and off-roading vehicles, four-wheel drive has actually been around for a long time. Even those rust-bucket pickup trucks that you see occasionally dotting rural roads may beIt equipped with this conventional mechanical technology.
Four-wheel drive is extremely useful in uneven terrain, where having all four wheels engaged gives the vehicle a better chance of going up over a rock or a bump. Four-wheel drive can be engaged when you need it, and then turned off when you don't.
What Is All-Wheel Drive?
All-wheel drive is a newer, more sophisticated technology. Unlike four-wheel drive, all-wheel drive is variable, which means it's automatically deployed. It might turn on without the driver even knowing. It works with electronic stability control (ESC), which is built into newer cars as part of a host of safety features that only became available in newer generations of cars.
ECS systems work using sensors that tell the vehicle's on-board computer if one or more wheels is spinning out of control due to contact with ice or rain. When the sensors relay data to the computer, it can adjust the differentials in order to provide better traction and handling for the vehicle. An ESC system working with all four wheels via all-wheel drive may keep slipping under control better than an ESC system in two-wheel drive cars.
Types of All-Wheel Drive
There are different kinds of all-wheel drive.
On-Demand All-Wheel Drive
When the system detects slippage, it routes power to the rear wheels. Otherwise, the front wheels move the vehicle.
Symmetrical All-Wheel Drive
Symmetrical AWD sends power to both axles, and then re-allocates that power when it senses a need.
Torque-Vectoring All-Wheel Drive
Torque-vectoring all-wheel drive distributes power between the front and back axles, and also between the two wheels on one axle. It can be good for precision handling and is usually associated with high-performance cars. Features like a viscous coupling and a multi-plate clutch can be effective in providing a certain type of all-wheel drive functionality for a vehicle.
Do You Need AWD or 4WD?
Now you know the difference. But what does that mean for you as a car buyer? The answer to that depends on how you typically use your car.
If you do a lot of driving on unpaved roads or other off-road terrain, you'll probably be better off getting a car with four-wheel drive. If you're mainly a street driver who cares and performance and the ability to handle changing weather conditions, all-wheel drive is going to be your best bet. But it's important to note that neither AWD nor 4WD help braking performance. In muddy or snowy conditions, they may help you get going, but if you're going too fast on ice or snow and lose control, these systems won't help you avoid a crash.