Available as an option, Vauxhall has further developed its IDS (Interactive Driving System) concept which was first seen on the Vectra and is now being introduced to the lower-medium sector for the first time.

IDS Plus sets new standards in achieving balance, ride comfort and active safety. In addition to ESP Plus and ABS, the IDS integrated network also integrates CDC (Continuous Damping Control). It is the kind of chassis technology previously seen only in higher priced segments and is another example of Vauxhall pioneering new technology within mainstream, affordable cars.

The sporting models within the range are also fitted with the new SportSwitch which at a push of a button, changes damper, steering and throttle settings. The sport mode also shifts the steering map towards "direct" for even quicker steering response.


Front axle: better ride quality, more responsive steering

The front axle of the new Astra uses further developed MacPherson struts with lateral control arms attached to a hydroformed sub frame. The new strut mounts are decoupled to reduce noise and vibration considerably. For improved initial response, the banana- shaped coil springs compensate to a greater degree for lateral forces acting on the shock-absorber piston.

To ensure a high quality ride for all engine variants, the spring rates are matched to the front axle load in 30 kg steps. These weight- dependent spring rates result in almost constant front-axle oscillation across the whole engine range - from 1.4 petrol to the 1.9 CDTi - despite variations of up to 200 kg in axle load.

New Astra's electro-hydraulic power-steering (EHPS) is map controlled which means that the car speed and the rate with which the wheel is turned determines the level of power assistance in every situation.

At the same time, a new steering knuckle has been developed to improve steering response, road contact and self-centering. Thanks to new production methods, Vauxhall can machine two lengths of steering arm - making available a more direct steering ratio (14:1 instead of 15:1) for Vauxhall Astra with sport suspension.


Rear axle: refined through intense engineering

At the rear, Vauxhall Astra uses a specifically adapted torsion beam axle with a double-walled, U-shaped profile. With the new model, this design combines all the advantages of a conventional torsion beam axle-like minimum space, low weight and high rigidity. Crucially, it can also be tuned precisely to the specific requirements of different models within the range.

In more detail, there are several key reasons as to why Vauxhall engineers opted for this simple but tried and tested design, including:

- high levels of stability through reduced camber loss under lateral force
- stable road behaviour and reduced tyre wear due to low camber and toe angle changes when loaded
- lower fuel consumption
- comfortable travel through reduced weight
- minimum space requirement allows greater flexibility in siting of the fuel tank and luggage area volumes.

In terms of the layout, this design helped the engineers keep the centre of gravity low for better handling and thanks to the compact design, the fuel tank fits deep between the wheels allowing a lower positioning of the rear seat.

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