Rear-Wheel Drive

Rear-wheel drive, abbreviated RWD, is a layout in which the engine's power is sent to the rear wheels, leaving the front wheels free to concentrate solely on steering. It is the classic configuration of the motor car, predominant for the first half of the twentieth century and still favoured today for performance, luxury and load-carrying vehicles. By separating the jobs of driving and steering between the two axles, rear-wheel drive allows each pair of wheels to do one task well rather than both at once.

In a typical rear-wheel-drive car the engine sits at the front, sending torque rearward through the gearbox and a propeller shaft to a differential mounted in the rear axle, which then drives the rear wheels. This arrangement spreads the major masses across the length of the car and helps achieve a balanced front-to-rear weight distribution, in the ideal case close to fifty-fifty. Good weight balance, combined with the absence of any driving forces through the front wheels, gives rear-wheel-drive cars their characteristically pure steering feel.

A key advantage is the elimination of torque steer, the tendency of a powerful front-wheel-drive car to tug at the steering wheel under hard acceleration. Because the front wheels transmit no drive, the steering stays clean and uncorrupted regardless of how much power is being applied. Rear-wheel drive also deploys power more effectively: during acceleration weight transfers rearward onto the driven wheels, pressing them harder into the road and improving their grip just when traction is most needed. This is why high-powered sports cars, saloons and many performance vehicles use the layout, and why it suits towing and heavy loads, which add weight over the driven rear axle.

The layout has drawbacks. With the driven wheels at the back and, in front-engined cars, less static weight over them, traction in snow and on ice can be poorer than front-wheel drive, where the engine's mass sits directly above the driven wheels. Rear-wheel-drive cars are also prone to oversteer, where the rear tyres lose grip before the front and the tail slides wide, especially if power is applied clumsily in a corner. In skilled hands this can be controllable and even enjoyable, but it demands more care from the driver, which is why modern rear-wheel-drive cars rely heavily on electronic stability control.

Rear-wheel drive contrasts with front-wheel drive, which is cheaper, more space-efficient and more secure for everyday driving, and with all-wheel drive, which combines the traction of driving every wheel with much of the balance of a rear-biased layout. The choice reflects a vehicle's priorities: front-wheel drive for packaging and economy, rear-wheel drive for handling purity and power deployment, all-wheel drive for all-weather security.