SUVs are the clear frontrunner in the Australian car market with a commanding lead over passenger vehicles, which once ruled the roost. As more buyers shy away from sedans and opt for SUVs instead, one common question pops up. What is the difference between 4WDs and AWDs? Unlike what you may have been led to believe, the two formats are not one and the same.
Four-wheel drive (4WD) vehicles rely upon a drivetrain that concurrently distributes torque from the transmission to all four wheels. Facilitating this is a transfer case, which ensures the load is distributed evenly so there is no imbalance in torque going to each wheel.
Because of the power afforded to each wheel, 4WD vehicles have an inherent upside. That is, they are built to handle off-road conditions, whether it be rocks, gravel or other treacherous conditions. On the other side of the ledger, however, 4WD vehicles also contend with a shortfall. That is, you often don’t need power supplied to each wheel when you are trying to turn.
As a result, many cars today come equipped with functionality that allows you to activate or deactivate the 4WD system. Alternatively, full-time 4WD vehicles rely on a differential to influence wheel speeds and adjust individual axles if needed. Differentials may also be incorporated into the vehicle to allow for ‘weighted’ power distribution.
Meanwhile, all-wheel drive (AWD) vehicles are a separate beast. They are not just restricted to SUVs, however, as many passenger vehicles, particularly wagons, rely on this type of setup.
Unlike 4WDs, this type of system is practically in operation at all times. That is, your car will be running as an AWD vehicle permanently, rather than certain 4WDs, which may be configured to run as 2WD when power to all wheels is unnecessary.
Mechanical AWD systems use a series of differential gearboxes to transfer torque to where it is needed. One of these differentials will transfer torque to the front axle, and another will transfer torque to the back axle. From there, each axle relies on another differential to transfer the torque to the wheels. In contrast, electronic AWD systems leverage sensors and an engine control unit to handle the distribution of torque to the wheels.
During instances where each vehicle is likely to require a different level of torque, AWD systems are particularly beneficial. Furthermore, they are suited to driving in wet conditions. They may not have the same prowess off-road as 4WDs, but their weight distribution and road handling qualities are often well-regarded.
Take note of these key differences if you are looking into a new vehicle. The more information you have at your disposal, the more likely it is you will walk away with a car that meets your needs.