About Dually Truck Wheels

The term "dually" refers to a truck with two sets of wheels on its rear axle rather than one. This provides a host of advantages including better handling, greater load capacity and safety benefits.

Function

The dually axle is the truck's non-steering axle. It has four wheels in total, two directly beside each other on each end of the axle. Since they distribute the truck's weight over more wheels, the tires last longer, provided they are properly rotated.

Benefits

According to the website Tire Rack, dually axles can handle twice the weight of non-dually axles. They also allow the truck to drive with a load temporarily in the event that one of the four rear axle tires goes flat.

Considerations

Dually trucks are more expensive than their non-dually counterparts, both in terms of initial purchase cost and tire costs. They are also wider than other trucks, making parking and driving through tight spaces more difficult.
Source:
About Dually Truck Wheels | eHow.com
Related Links:
Putting new tires on a dually pickup truck
How to Change Dually Tires | eHow.com
How to Remove Outside Dually Wheels | eHow.com

********


Okay, the point is: Can we inspire from this pattern to have a better situation for electric vehicles, especially in case of power-generating and confidence (in stability & safety)? I think so. Interestingly, the idea of dual wheels has been realized in some vehicles:
1, 2, 3, 4, 5, a cool vehicle for my desired trips, not dually wheeled, but nice, …

On the other hand, any single wheel of rear axle has to handle the (weight of) car for a suitable duration & distance. This property is what one expects in the worst situation that one of the dual wheels is out of order for some reason.
The outside wheel can be designed in a way that functions as a normal wheel, while the inside wheel has the additional duty of power generating as it was described before (post #54).


****

Whenever there is a need to more electricity, the outside wheels can be lifted up a bit for a short duration. Also, whenever there is need to power-generating elements to rest, the inside wheel can be lifted up a bit. In both conditions, the car is moving normally, but maybe the mentioned operations would need more caution in high speeds and rapid rotations.
Also, in contrary with traditional characteristic of dual rear wheels in pickup trucks in flaring the rear wheel arches, and their application as heavy-duty towing and hauling vehicles, we might not need wide wheels for the rear axle. Similar to this image: