Understanding your vehicle’s capabilities will lend you confidence on and off the road.
Marc Urbano / Car and Driver
While it’s easy to think that AWD and 4WD systems are relatively similar, both drivetrain layouts are actually quite different. Long story short, all-wheel drive is designed to optimize on-road traction while 4WD is more of a one-trick pony for off-road applications. The best way to highlight the differences between the two requires us to go back to basics and explain how a vehicle goes around a corner successfully.
Regardless of the size, power, or weight of your vehicle, when you go around a corner, the outside wheels have to travel farther than the inside wheels. If you are the proud owner of an AWD vehicle, you may have noticed that the system is on all the time (we’re disregarding part-time AWD systems that only kick in when they sense a loss of traction), while certain 4WD vehicles allow you to switch 4WD drive on and off. This is because AWD vehicles use three differentials, which allow the wheels to turn at different speeds. However, with selectable 4WD activated, this will lock the center differential connecting both axles, meaning that all of the wheels are forced to turn at the same speed. Therefore, if you went around a corner with 4WD engaged, you’d hear the driveline make some pretty nasty noises, your tires might hop and chatter, and your turning radius would suddenly be quite poor.