Understanding All-Wheel and Four-Wheel Drive

Dear Tracy,
Can you tell me if there is a difference is between all-wheel drive and four-wheel drive, or if these terms mean basically the same thing? I am also wondering if it is worth investing the extra cash to get an all-wheel or four-wheel drive vehicle. Is the safety and performance that much better?
Andrew J.

Dear Andrew,
To answer your first question, all-wheel drive and four-wheel drive are not the same. In the design of an all-wheel drive vehicle,  the drivetrain has a front, rear and center differential to provide power to all four wheels of a vehicle. The drivetrain on a four-wheel drive vehicle has two differentials and a transfer case to provide power to all four wheels of a vehicle. Cars and crossover vehicles often have all-wheel drive, while trucks and truck-based sport utility vehicles typically have four-wheel drive. Both all-wheel and four-wheel drive systems can improve vehicle acceleration in slippery conditions, and may offer better handling on some types of roads or terrain.

As to whether or not these systems are worth the extra investment, the answer will depend largely on the conditions under which you normally drive and what kind of driving you do. If you live in an area that gets heavy rain or snowfall for most of the year, the investment may be worth it. Similarly, if you do a lot of off-road driving or driving on unpaved roads, all-wheel or four-wheel drive may be highly beneficial. Some other advantages to having all-wheel drive or four wheel drive include better traction with towing and often times, added resale value.

On the downside, there are other drawbacks, besides the additional cost that you noted. All-wheel and four-wheel drive vehicles offer lower fuel economy and require more maintenance than standard vehicles. In regard to gas consumption, it is important to note that four-wheel drive, unlike all-wheel drive,  can be turned off so you have the option to only use it, and the extra gas it requires, when you need it.

In deciding whether or not to invest in all-wheel or four-wheel drive, remember that in many cases, such as winter driving, selecting the right type of tire may be the best thing you can do to enhance safety and performance.