Delta II is General Motors' current compact car platform, which was developed by Opel in Germany. It is the successor to the GM Delta platform. Internally it is simply known as a new Global Compact Vehicle Architecture or GCV.
The platform features a torsion beam rear suspension with optional Watt's link which improves vehicle handling; such configuration is used in the Opel Astra and some trim-levels of the American-market Chevrolet Cruze. This suspension is usually described as semi-independent, meaning that the two wheels can move relative to each other, but their motion is still somewhat inter-linked, to a greater extent than in a true independent rear suspension (IRS). This can mildly compromise the handling and ride quality of the vehicle. For this reason, some manufacturers have changed to different linkage designs. As an example, Volkswagen dropped the torsion beam in favour of a true IRS for the Volkswagen Golf Mk5, possibly in response to the Ford Focus' Control Blade rear suspension. General Motors in Europe Vauxhall/Opel have continued to use twist or torsion beam suspension. This is at a cost saving of €100 per car compared to multi-link rear suspension. Their latest version as used in the 2009-on Opel Astra uses a Watts linkage at a cost of €20 to address the drawbacks and provide a competitive and cost effective rear suspension. The Renault Megane and Citroen C4 also have stayed with the twist beam. The twist beam has been shown to suffer less from bush wear, than fully independent multi-link suspension.
GM chose this compact vehicle architecture for its first Voltec application, the Chevrolet Volt. Production began in November 2010 with the first Chevrolet Volts delivered to retails customers in December 2010
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