The removal of a car's fixed roof presents significant engineering challenges, primarily related to
torsional rigidity — the chassis' resistance to twisting during cornering or on uneven surfaces. Audi
addressed this challenge in the A5 Cabriolet through an extensive program of structural reinforcements.
Body Reinforcements and Safety
To compensate for the absence of the roof structure, the A5 Cabriolet's platform received
ultra-high-strength steels at critical points. The door sills (the lower part of the side structure) were
reinforced, as were the central transmission tunnel and the A-pillars (which support the windshield). The
result is a body that maintains dynamic integrity, preventing the excessive vibration known as scuttle
shake, common in less rigid convertibles.
In terms of safety, the model introduced an active rollover protection system. Aluminum bars, hidden behind
the rear headrests, are pyrotechnically deployed (by controlled explosives, similar to those in airbags) in
milliseconds if the vehicle's gyroscopic sensors detect a dangerous tilt or imminent rollover. Additionally,
special head-thorax side airbags were developed to protect occupants even with the windows down.
K-Fold Soft Top Technology
The A5 Cabriolet's fabric soft top is a complex piece of engineering, designed to offer thermal and acoustic
insulation comparable to that of a closed vehicle. Audi offers an "acoustic soft top" composed of three
layers, including a middle layer of polyurethane foam that absorbs external sound frequencies, allowing
conversations at a normal tone even at highway speeds.
The opening and closing mechanism uses a kinematics known as "K-Fold", which allows the roof to fold
compactly in the rear.
- Opening Time: 15 seconds.
- Closing Time: 17 to 18 seconds.
- Operation on the Move: The system can be operated at speeds of up to 50
km/h, an essential functionality for sudden weather changes in urban traffic.
- Impact on Trunk Space: When retracted, the soft top occupies only about 60
liters of the luggage volume. The trunk offers 380 liters with the top closed and 320 liters with it
open, maintaining the ability to fold down the rear seats to transport long objects.