This neat city car concept hides a secret under the skin, which could help automakers develop lighter and more compact electric cars.

The WILL hatchback is the first car to feature Michelin’s new Active Wheel, which integrates electric motor, brakes and suspension functions inside the wheel. The car is now under test in France. It has been developed by contract manufacturer Heuliez, and also acts as a showcase for the company’s capabilities.

Heuliez is best known for producing versions of Citroen and Peugeot cars – such as estate derivatives – where volumes are too low to justify full-scale production investment by the automaker.

Heuliez’s assembly plant in Cerizay, France, has the capacity to produce the car, and the company plans to build “several thousand vehicles” a year from 2010.

The Michelin Active Wheel allows automakers to make massive weight savings, as it allows them to do away with traditional engines, gearboxes and transmission shafts. It’s taken 12 years to develop, but the launch could be timely, with so many automakers looking to develop electric car programmes.

Inside the wheel there is a small electric motor, an electric suspension system and a brake disc. The Will has two Active Wheels, driving the front wheels, but a bigger car, or a performance-oriented vehicle could have four Active Wheels. French sports car maker Venturi is developing a coupe concept called the Volage, which will have four Active Wheels.

The wheel makes it possible to completely rethink the car, says Heuliez. There is no need for a gearbox, clutch, transmission shaft, differential or shock absorbers. The wheel also offers the possibility of a totally flat floor, maximising interior space and under-car aerodynamics, and also freeing up space inside the car for battery packs or fuel cells.

The WILL can seat five, it has luggage space at the front and rear, and the electric drivetrain offers a range of 150km with a lithium-ion battery pack.