AWD vs. 2WD: when and how to choose
Four-wheel drive (or 4WD) is often used for both off-road and on-road vehicles. All-wheel drive (AWD) differs from 4WD in that power is transmitted to all four wheels, as opposed to a two-speed transfer case and drive axles. Two-wheel drive (2WD) is the drive-type found in most cars. In 2WD vehicles, the power can be directed to the front wheels (FWD), pulling the vehicle, or rear wheels (RWD), pushing the vehicle. Both drive types offer advantages and disadvantages, especially when it comes to high-performance.
Difference between 4WD and 2WD
With 4WD, all four wheels receive power from the engine through the drive train. In 2WD, only the front or rear axle receives power. The non-powered axle just rotates, either following the direction of the power and steering or also controlling the steering.
High-performance vehicles and drive systems
Having 4WD on high-performance trucks or SUVs is an excellent option if you plan to do any serious off roading. It can also be beneficial in heavy snow, or if you want to use your vehicle for towing. Unfortunately, using a 4WD system on dry pavement can cause the driveline to bind, especially in turns; the system is designed for road conditions where all four wheels spin independently.
Hence, AWD is the better choice for performance. Compared to RWD it’s difficult to produce tire-smoking burn-outs, and there’s increased drivetrain loss as well as lower fuel economy. But launches can be easier since all four wheels are moving the car off the line. The use of a limited-slip differential delivers power when tire slip is detected by the computer system. AWD and limited slip differentials can be found in the Lamborghini Murcielago, Mitsubishi Lancer Evolution and Nissan GT-R, to name a few cars.
The 2013 Porsche 911 Carrera 4 Cabriolet is the perfect example of AWD and high-performance. Porsche uses a rear-biased AWD system with a traction management system. This vehicle has mastered the combination of economy and performance.
If you define performance as speed and handling, you want a RWD vehicle or an AWD vehicle. If you define performance as climbing mountains and plowing through snow banks, get a vehicle with 4WD.
Content by Barbara L Baird.