How quattro® works
Front wheel drive
Front wheel drive allows the car to be pulled which increases the amount of tractive force it can transmit to the road compared to rear-wheel drive. The weight of the engine and other assemblies rests on the front axle and thus increases traction to the driving wheels. If they start to lose traction, the front-wheel drive vehicle understeers and tends to continue straight ahead although the front wheels are turned. This is a relatively mild effect that the driver can normally control by simply lifting their foot off the accelerator.
Traction aids such as ASR and EDL are fitted as standard on all Audi front-wheel drive vehicles. Additionally the ESP Electronic Stability Program greatly enhances what is already a high level of safety.
Rear wheel drive
The vehicle is pushed along by the driven rear wheels. As an initial situation, this is fundamentally less stable than with front- or all-wheel drive. If the driven wheels spin, the rear-wheel drive vehicle tends to oversteer and its tail may then slide sideways.
To guard against this situation arising, which the driver may find fairly difficult to control, the corrective action of traction aid systems and electronic stability programmes takes effect quite early. The vehicle can be kept moving safely, but traction is reduced by the need to apply the brakes at individual wheels, so that driving the vehicle becomes less pleasant.
quattro® permanent All-wheel Drive
Permanent all-wheel drive offers an unusually high level of active safety. In terms of tractive force, acceleration and hill-climbing ability on a poor surface it is unbeatable. By distributing the power input from the engine between two axles, higher lateral locating forces can be absorbed when cornering. This enhances lateral acceleration and at the same time ensures the highest possible level of safety.