Italian manufacturer Ferruccio Covini's radical six wheeler, the C6W, has been in the pipeline since the mid seventies. Unfortunately due to safety concerns and general engineering and the costs involved the concept has only recently come to fruition. Covini began work on the six-wheeler with backing from larger companies to help finance its development.
The reasoning behind the four front wheels is mainly inspired by safety concerns, two front wheels at each corner means a front tyre blowout will not cause the vehicle to lose control, because of the additional supporting wheel. Then there's the additional stopping power afforded by four front discs and four tyre footprints to transmit the force - although the individual area of each tyre footprint is smaller than that of a traditional tyre, the total area is greater.
Covini also claim there is less risk of aquaplaning because the two foremost wheels clear the water for the ones behind and allow better road adhesion.
Comfort is another consideration - less unsprung weight at each wheel allows the suspension to control wheel movement better and the overall ride benefits from more evenly distributed reaction forces in the suspension.
The drop in the individual unsprung weight of each wheel also offers much better grip and better directional stability - with a well-matched set of tyres, a six-wheeler can be expected to have higher cornering speeds than a four wheeler.