nstrahan

Seconded. The wheel bolted joint works by friction. The joint is tight enough that the wheel is effectively "welded" to the hub. That is, any in-plane loads (vertical or transverse in the vehicle orientation) are transmitted to the hub by the friction between the wheel and the hub. If the hub bore were what was bearing the load, the hub would have to be a near perfect slip fit, which would make assembling the wheel extremely difficult. If the fit were any looser, the wheel would fret (slide) against the hub, and eventually cause a fatigue failure.

I agree that the hub bore on the wheel exists to center the wheel only. In a lug centric wheel, the wheel is self centered during the torqueing of the lugs. However, in both cases, the loads are carried exclusively by the friction in the joint.

Periodoc

I think that if the hub supported the weight of the car, the tolerances would be so small that you'd have to hammer the wheel onto the hub. If you've changed tires, then you know this.