What Wheel Drive?
Front-wheel-drive, rear-wheel drive, all-wheel-drive, four-wheel-drive — these terms refer to which of your car’s wheels get power from the engine. But what are the advantages and disadvantages of each, and which setup is best for you? That’s the subject of this edition of Vroom Girls University.
By Aaron Gold
Front-wheel-drive (FWD) is the most common drivetrain layout in use today. With FWD, all the bits that make the car go are neatly packaged under the hood, which saves weight and frees up interior space.
Advantages of front-wheel-drive:
- Allows smaller cars to have more interior space and trunk room
- Weight of engine right over the drive wheels gives good traction in rain and snow
- Front-wheel-drive vehicles are usually lighter, which improves gas mileage
Disadvantages of front-wheel-drive:
- Doesn’t deliver as much of a sporty driving feel as rear-wheel-drive
- Powerful FWD cars are subject to torque steer, a tendancy to pull to one side under hard acceleration
- With all the mechanical bits crammed together, repairs can be more time-consuming and expensive
Until the 1980s, most vehicles sold in America were rear-wheel-drive (RWD), but it was largely abandoned as buyers turned to smaller cars. Today, RWD is making a resurgance in performance-oriented sports cars. Most rear-drivers have the engine in front, but some have the engine at the back. Most pickup trucks use rear-wheel-drive, as do a handful SUVs.
Advantages of rear-wheel-drive:
- Provides sportier, more controllable handling and better steering feel, especially in very powerful cars
- Reduced mechanical complexity
Disadvantages of rear-wheel-drive:
- More cramped interior due to driveline “tunnel” running the length of the car between the seats
- Trickier to drive in wet or snowy weather – easier to spin out in bad weather than FWD
All-wheel-drive (AWD) and four-wheel-drive (4WD) both deliver power to all four of the car’s wheels, but there are different types of systems with significant differences in operation.
All-Wheel-Drive or Full-Time Four-Wheel-Drive
These systems are entirely automatic, requiring no driver intervention. Most of these systems deliver all of the engine’s power to one pair of wheels (usually the front) until those wheels begin to lose traction. When that happens, the system begins to shift power to the other wheels until the car regains traction. All-wheel-drive is most commonly found in SUVs and crossovers, but is also used in sporty cars as a way to improve their handling.
Advantages of all-wheel-drive:
- Entirely automatic; driver does not need to manually engage four-wheel-drive
- Best choice for inclement weather; also works well on dirt and mud
- Provides improved handling and better tire “grip” in sudden panic swerves
Disadvantages of all-wheel-drive:
- Greater weight and increased fuel consumption compared to front- and rear-wheel-drive
- Faster tire wear than front- or rear-wheel-drive
- Not suitable for hard-core off-roading
Part-time 4WD systems require the driver to manually shift from two- to four-wheel-drive. These systems usually have a low range setting (labeled “4 LOW” or 4 LO”) for extreme off-road use. Unlike full-time systems, part-time systems usually lock the front and rear axles together, providing a 50/50 front-to-rear power split. Part-time 4WD is most commonly found in pickup trucks and heavy-duty SUVs. Some part-time systems have an automatic setting that provides the same functionality as a full-time system.
Advantages of part-time four-wheel-drive:
- Best choice for serious off-roading
- Least likely to get stuck in mud, dirt, or uneven terrain
Disadvantages of part-time four-wheel-drive:
- Requires the driver to manually engage four-wheel-drive; otherwise traction is not much better than a rear-wheel-drive vehicle
- Four-wheel-drive operation may be limited to off-pavement use
- More rapid tire wear when operated in four-wheel-drive mode
Volkswagen Group of America, Inc. is not responsible for the content of this column.