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What is the difference between AWD and 4WD?

What is the difference between an All-Wheel Drive (AWD) car and a Four-Wheel Drive (4WD) car? Both cars drive all four wheels so in one sense there is no difference except that AWD has become an accepted description for a car that drives all of the wheels, all of the time. 4WD is generally accepted as a car or more typically a larger SUV (Sports Utility Vehicle) that uses a driver selectable system that mechanically engages the drive to all four wheels. If you are thinking about buying a new Subaru vehicle, and you are looking for information about the differences between an AWD system and a 4WD system, then this article by Pfaff Subaru in Guelph will be informative for you! Let’s take a look at some of the differences now.

 

The 4WD System

4WD is normally used on large SUV Four-Wheel Drive (4×4) vehicles designed to use the extra traction of 4WD in off road situations. These vehicles are predominately truck based platforms with large wheels and off road tires that combined with a manually selected and a locked 4WD driveline enables the vehicle to venture off-road and negotiate very difficult terrain.

 

A locked 4WD driveline means that there is direct mechanical link between front and rear axles with no mechanism to allow any difference in the number rotations of the front and rear axles. This means that when the 4×4 vehicle turns a corner because the radius of turn is different for front and rear axles, the tires on the axle with the smaller radius of turn must be able to slip on a loose slippery ground surface. If the ground surface is not slippery and the tires do not slip, then the driveline (axles and propeller shaft etc) will twist and stress will be induced.

 

The AWD System

Crossover small or medium SUV All-Wheel Drive cars such as the Subaru Forester, that are designed for normal road use, with occasional dirt or mild off road, generally use permanently engaged AWD systems. This has the active safety advantage of always having twice the grip of a driver selectable 4WD system. This means that in the unexpected situation where the corner is more slippery than expected or when immediate traction is required to move safely into merging traffic, All-Wheel Drive is already engaged, and the required level of traction is available to safely negotiate the situation.

 

The best SUV, therefore, from an active safety point of view is an AWD vehicle that does not require driver selection to drive all four wheels. This is because twice the level of traction is always available to get out of that difficult situation when a split second can make the difference between life and death.

 

If you are looking for more information about the differences between AWd and 4WD systems, then we encourage you to consider visiting our Pfaff Subaru dealership in Guelph and speaking to our representatives today! Click here to find our contact information, schedule a test drive, or to fill out our contact form.