I have now modified my drawing and text located at...
www.bluffton.edu/~edmistonm/Car.Tires.pdf
I think the document is more clear now. It is the same as I was saying
before, but it is drawn better and stated better. I also changed the
cross section of the wheel's rim since John pointed out my original
drawing was incorrect.
I think it has always been correct for me to say that the wheel (and
hence the car's weight) "hangs" from the upper sidewall of the tire. It
is less obvious whether one should say it hangs from the bead or is
supported by the cradle of the bead, or words like that.
To some extent I would still say that it hangs from the bead because the
bead is practically glued to the rim. If the bead were loose on the rim
then the wheel couldn't hang from the top bead and would have to be
cradled by the lower bead. But the bead does not slip (neither
vertically nor circumferentially when we accelerate). Therefore the
bead and rim are essentially a rigid unit. In that sense I think I am
now inclined to say that the wheel/rim/bead unit hangs from the upper
sidewall.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu