I'm about to the point of thinking it doesn't matter whether we treat the
bead/rim/wheel as a unit, or treat the bead separate from the wheel. It
seems to me the major point is that the wheel is supported by essentially
hanging from the upper sidewall rather than being pushed up by the lower
sidewall. That's the thing the average person doesn't understand. The
interaction between the bead and wheel is probably some combination of glue
or friction with the rim on top as well as tension from the cables in the
bead. Doesn't it have to be some combination, because they are both
present. I just don't know the ratio.
Although I am mostly thinking it doesn't matter what the ratio is (that is,
the bead is pretty darned-well stuck to the rim somehow), I am trying to get
some information for a local tire manufacturer. Cooper Tire and Rubber
Company national headquarters is in Findlay, Ohio which is 20 miles north of
where I live. They do most of their testing and design in Findlay. I know
one of the rubber chemists who works there. I am trying to get him to put
me into contact with one of the tire engineers. However, this appears
somewhat difficult because they seem to claim a lot of "proprietary
information" when you try to talk details. As part of our local American
Chemical Society group, of which I am a member, I have toured the plant
several times. It's a great and amazing tour, but they don't answer very
many detailed questions. I think they know the answers... they just "ain't
talkin." I'll see if I can spring any information loose about this bead/rim
question.
Anybody else know any tire engineers?
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
1 University Drive
Bluffton, OH 45817
419.358.3270
edmiston@bluffton.edu