TURIN - Michelin's Pax tire system allowed the Italian coach builder and design firm Pininfarina to 'reinvent the car,' said chief engineer Paolo Garella.
The result is the Metrocubo, which has been called Italy's answer to DaimlerChrysler's Smart. Garella said the hybrid urban car was born out of the Pax tire system.
Pax uses a new technique of attaching the tire to the wheel rim. A flexible support ring, similar to a solid tire tube, is fitted between the tire and rim. The tire does not need air pressure to bond itself to the rim, which means the rubber will not separate from the metal during a flat tire.
Pax gave Pininfarina a variety of design options, starting from basics such as ease of access, modularity and comfort, Garella said.
Normal design limitations, such as the size of tires or the impossibility of having different-size tires and wheels on each axle, have been overcome. The Metro-cubo, which means 'cubic meter' in Italian, has small, narrow front wheels and large back wheels. Because of the run-flat Pax system, a spare tire is not needed.
This unusual format opened up opportunities for technical solutions that may seem daring but proved to be practical, Garella said. The Metrocubo, which is less than 119 inches long and about 68 inches wide, is highly maneuverable. It has a turning circle of just 25.4 feet.
The car has a highly flexible interior thanks to its low, flat floorpan, and it can carry up to five passengers.
The Metrocubo has two sources of energy: a generator unit and a battery pack. The generator includes a Lombardini 500cc, two-cylinder gasoline engine and a Vickers generator. The entire unit is water-cooled. The generator intervenes when the battery charge falls below a set level.
It is possible to override the generator system. For example, in town the Metrocubo can travel electrically as a true zero-emissions vehicle.
In the all-electric mode, the car has a range of about 25 miles. With a full tank of gasoline, Pininfarina estimates the Metrocubo's range to be 125 to 250 miles.