Some say it does support the weight of the car. I tend to belive that it is only used for centering the wheels while they are mounted. Othewise most rings are plastic and no way it could support the weight of the car. The metal ones arent any stronger either to bear the load.

"Hubcentric" is another term that is often not mentioned or is misunderstood. A hubcentric wheel is a wheel designed with a centerbore opening to match the exact diameter of the hub of a specific vehicle. The importance is that the weight bearing of the wheel, in reference to the vehicle, is accomplished by the hub and centerbore mating to an exact fit. The lug nuts/bolts' only purpose is to affix the wheel to the mounting surface, not to bear the weight of the vehicle. Often wheels that are not hubcentric create driveability problems--shimmy, vibration, and erratic tracking. Many quality manufacturers design their wheels to be versatile by providing hubcentric centering rings that snap into place inside the wheel, to make the wheel hubcentric. This is an important safety issue--hubcentricity is highly recommended. "

"The other element that affects directly whether a wheel can be bolted onto a car is hubcentricity. Long ago, in the deep mists of time, wheels were located by the taper of the lug nuts or bolts. This could lead to all sorts of problems, but they can be summarized by saying centering was liable to be less than perfect, and the sheer stress on wheel bolts or studs could be enormous. I am not aware of any passenger car wheels now made that are not hubcentric. Hubcentric wheels have a hole at their center that fits closely over a round feature on the hub, serving to center the wheel on the axis of the spindle, as well as bear the vertical weight of the vehicle. The wheel bolts or studs then serve simply to hold the wheel onto the hub, and are loaded only in tension, where they are strong. If the studs were required to absorb vertical forces, they would be loaded in single shear, the weakest arrangement for any fastener. Factory wheels are all machined to fit their specific application exactly, and some of the better aftermarket wheels are, too. However, many aftermarket wheels rely on centering rings. This means that, instead of machining wheels specifically for each O.E. centering hole diameter, the wheel manufacturer machines all wheels to one size, and then uses inserts to give a centering surface of the diameter required for each application. This is obviously easier to do, and makes inventorying a complete wheel line much simpler and less costly. If you buy wheels that use centering rings, be sure the rings fit snugly in the wheels. If they are loose enough to fall out, how accurately can they be locating your wheel? Some tire shops automatically remove centering rings to balance a wheel, just to make sure there is no slop to make their balancing inaccurate. The fact that a wheel physically bolts onto a car doesn't necessarily mean it "fits." The centering surface could be too large, in which case there essentially is no centering. Just as importantly, the offset could be wrong. "

 

so there is no way they can support 3200lbs or even a fraction of that... unless you get into huge fractions ;-)