Audi TT MK1 running gear

The McPherson three-legged-arm axle with auxiliary frame and cross-stabilizing bar was designed as a sporty suspension chassis. In order to improve directional stability, a newly developed steel cast iron pivot bearing was used with modification of the connection to the steering bars as well as a new forged arm.

The characteristics are:

• Track rod ball joints (greater articulation angle)
• Guide ball joint reinforced with thicker studs
• Subframe securely bolted with an aluminium bush
• The strut-to-stabilizer bar connection ensures better response behavior

Torsion beam axle with anti-roll bar

The 25° inclination of the bearings gives the rear axle a favorable self-directional behaviour.

The drift forces generated in the turns are induced in the landing due to the inclination of the rear gear, which is a good thing, and then are transmitted by the landing to the body.

The damper support is located in the wheel arch and that of the coil springs under the spar. The dissociation of springs and shock absorbers creates a spacious luggage compartment and transmits a minimum of noise in the cabin (acoustic decoupling).

The stabilization of the axle is achieved by a tubular transverse stabilizer bar.

Longitudinal double-wishbone rear axle with Haldex coupling

• The attachment of the axle with superimposed arms is carried out by means of the auxiliary frame (4-point attachment) and the respective track corrector axle bearing mounted on the longitudinal arm.
• Stabilization is provided by a transverse stabilizer bar on the auxiliary frame of the axle
• Mounting position of shock absorbers (approx. 45°)

The first models of TT encountered a problem of stalling the rear gear when changing direction at very high speed (over 160 km/h). This marginal problem, but with heavy consequences, forced Audi to improve the stability of the rear on vehicles in production and to recall vehicles already produced.

The changes were as follows:

• addition of a dynamic path control system (ESP)
• addition of a fixed rear spoiler generating 43 kg of additional lift on the rear at 200 km/h
• modification of the front anti-roll bar 20 mm in diameter (instead of 19 mm)
• Relocation of the front control arm mounting points (moved back by 45 mm)
• Modification of the front/rear spring and damper assemblies (firmer settings)

The manufacturer's recall by Audi allowed the modification of vehicles free of charge, except for the ESP system which was billed at the option's catalog rate.