The Difference Between All-Wheel Drive (AWD) & 4-Wheel Drive (4WD)

Have you ever wondered what the difference was between an all-wheel drive (AWD) & 4-wheel drive vehicle? Many people do, and for good reason, as the 2 could be mistaken for one another (or appear to be the same).

However, this blog article will show you the exact difference between the 2 (because there is).

Four-Wheel Drive (4WD or 4×4)

In a 4-wheel drive vehicle, the power goes from the transmission to what is known as a transfer case. This process then splits power between the front and rear axles so that maximum torque goes to each wheel, a system that still powers brands such as Jeep.

When the transfer case splits power evenly, each wheel turns at the same speed, which is a problem. For a car to make a turn, the inside wheel has to turn more slowly than the outside wheel, which cover more ground. So, in a 4WD vehicle, the inside wheel loses traction and spins freely. However, modern 4WD systems get around this as most modern 4WD systems are only on when you activate them. That way, you can use 4WD at low speed in snow or mud, but enjoy the drivability of two-wheel drive in normal conditions.

4WD Pros

  • Best traction in off-road conditions
  • Can be turned off to improve fuel economy
  • Proven, rugged technology

4WD Cons

  • Adds weight and complexity to cars
  • Can’t be used in all conditions
  • More expensive than two wheel drive models

ALL-WHEEL DRIVE (AWD)

The biggest difference between 4WD and AWD is that an AWD drive system is on most of the time, and there are two types of all-wheel drive: mechanical and electronic.

The most common mechanical AWD system uses three differentials. A differential is a box of gears that can take power from the transmission and split it at different levels between two wheels or the front and rear axles (four wheels).

In AWD, this system works to get power to the wheels with the most traction by splitting power between the front and rear axles on the center differential, and the individual wheels by way of the front and rear differentials. This is useful either in slippery conditions when different wheels might be getting different amounts of grip from moment to moment. Although AWD can’t match the traction of a 4×4 in extremely low-speed off-roading, not everyone needs it.

These days, computers and other electrical systems are involved in most AWD systems. Sensors on each wheel monitor traction, wheel speed, and several other data points hundreds of times a second. The ECU (engine control unit) dictates where power is sent and to which individual wheel depending on whichever has the most grip.

AWD Pros

  • Provides increased grip and control under all road conditions
  • Gives sportier handling and traction to a broader range of cars
  • Works all the time

AWD Cons

  • Reduces Fuel Economy
  • Increases the weight and complexity of vehicles
  • Not as good in extreme off-road conditions

SO WHICH IS BEST FOR YOU?

If you plan on using your vehicle off-road often, 4WD is definitely the way to go. 4WD appears on pickups and truck-platform SUVs that have the durability to match a 4WD system.

For most people, however, AWD makes more sense. Most vehicles featuring AWD tend to have better weight distribution, which aids in traction (and performance). In the sort of winter road conditions that most Minnesota drivers experience, it’s nice to have a drivetrain, like a modern AWD system, that responds instantly without the driver having to toggle any switches.