Agility combined with high levels of safety were the objectives for the new Astra suspension. The front is a further evolution using MacPherson struts with lateral control arms attached to a hydro formed sub frame at the rear. The new strut mounts are decoupled, to effectively reduce noise and vibration.
To ensure equality in ride comfort across all engines, the spring-rates are adapted to the front axle-load in 30 kg steps. The weight-dependent spring rates allow a consistent ride-frequency of the front axle across the range, from the 1.4 TWINPORT to the 2.0 turbo – and this, despite up to 200 kg variation in axle-load.
The rear of the new Astra features a specially adapted torsion beam. The layout combines the space saving advantages of a conventional torsion beam axle with low weight and consistent "camber control". It can also be easily tuned for the different models within the range.
Additional benefits of the suspension include giving the new model an improved ‘stance’ and more interior space from the wider tread, while noise is reduced from the larger, 70mm bushings. Intensive development of the beam’s twisting characteristics also results in improved driving stability.
The space-saving layout of the rear axle helped the engineers to achieve a low centre of gravity while the fuel tank fits between the wheels, enabling lower positioning of the seats.
Astra’s electro-hydraulic power-steering (EHPS) is map controlled so that power assistance varies according to the car speed and amount of steering input.
With those models fitted with Sport mode, the steering mapping can be changed to "direct" at the push of a button.
New flexible manufacturing techniques mean that Vauxhall will offer two lengths of steering arms on the new Astra, with a more direct steering ratio (14:1 instead of 15:1) being available in combination with the sport-chassis.Published 15 December 2003