The current Phantom Series II is based on the aluminium spaceframe that Rolls-Royce owner BMW derived from the Z8 roadster programme in 2003. So it is in need of a replacement anyway. The current Ghost Series II rides on the platform it loosely shared with the previous generation 7 Series - and the Wraith spawned off that too.
The company promises to have test mules driving on actual roads soon, which will test among other things - how to tune the new platform to maintain Rolls-Royce's signature 'magic carpet ride'. The picture released by Rolls-Royce shows a test mule, that still appears to be a Phantom, but the rear has been masked in bright light. This disguises whether or not we see a crossover/wagon-like roofline or not - which is intentional, as that is what I reckon we can expect the upper silhouette of the crossover to be like too.
Torsten Muller-Otvos, CEO, Rolls-Royce Motor Cars said, "Since 2003 Rolls-Royce Motor Cars has reset the benchmark for luxury motoring. Now it is time to take the next step in the luxury journey. This is why I am announcing today that on-road testing of our all-new proprietary architecture is beginning. This new architecture of pure luxury represents considerable investment in the future of our great brand."
The new architecture will allow Rolls-Royce to gain in many ways. Agility, greater stiffness, performance, refinement, reduced tyre noise and ride quality will be the most obvious benefits. But more important from the manufacturing point of view will be the advanced electrical architecture that goes with it. This will allow Rolls-Royce cars to have an option of electrification and possible hybrid powertrains. It will also mean being able to offer even more sophisticated features like autonomous driving, active steering, and the new 7 Series' gesture control.
Soon after announcing Project Cullinan in February 2015, Rolls-Royce had begun testing a new all-wheel drive system using Phantom-based test cars. The new SUV will use that system, and the new architecture - and is slated to arrive to market in early 2018. It will be followed quickly by a new Phantom. Expect the new Ghost and Wraith only post 2020.