2019 Audi A7 All Wheel Steering Explained – Video
The new A7 further extends its synthesis of sportiness and comfort. The optional dynamic-all-wheel steering, the new electronic chassis program (ECP) – the central controller for the chassis – and the updated air suspension make it even more agile, nimble and comfortable. The A7 is thus the perfect Gran Turismo: dynamic and agile on twisty country roads, yet comfortable on long highway stretches.
Many aspects of the front and rear axles have been developed from scratch. The standard progressive steering, whose generally sporty ratio becomes even more direct the further the steering wheel is turned, features a new concept for intensive road feedback. Mounted behind large wheels – up to 21 inches and 255/35 – with improved rolling comfort are aluminum fixed-caliper brakes with discs up to 400 millimeters (15.7 in) in diameter. Customers can choose between four suspension setups: a conventional steel spring suspension, the sport suspension that lowers ride height by 10 millimeters (0.4 in), electronically controlled damping and the self-leveling adaptive air suspension.
The top chassis-related innovation is dynamic-all-wheel steering. It combines direct, sporty steering response with unshakable stability, resolving the conflict of aims between agility and comfort. The steering ratio varies as a function of speed between 9.5:1 and 16.5:1 by means of active steering interventions at the front and rear axle. At the front axle, strain wave gearing is used to superimpose these in response to the driver’s steering input. At the rear axle, a spindle drive turns the wheels by as much as 5 degrees. At low speed, they steer counter to the front wheels to further increase the agility of the big coupe when parking or driving in urban traffic, for example. This reduces the turning circle at full lock by 1.1 meters (3.6 ft). At 60 km/h (37.3 mph) and above, the rear axle steers in the same direction to increase straight-line stability and facilitate lane changes.
The optional sport differential improves handing even further. It actively distributes drive torque between the rear wheels, complementing quattro all-wheel drive. Like dynamic-all-wheel steering, controlled damping and the adaptive air suspension, the sport differential is integrated into the control function of the electronic chassis platform (ECP). These systems are closely networked for maximum precision. The driver can use the Audi drive select system to activate different ride profiles featuring a more pronounced difference between comfort and sportiness than in the previous model.