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Old 04-09-2009, 11:54 PM   #4 (permalink)
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Originally Posted by Ernie Rogers View Post
. . .

Rubber Internal Friction and Stiffness

Some kinds of rubber are much more “efficient” than others. Remember super-balls? They were so surprising because they could bounce up almost as high as they fell. The ratio of <bounce up> to <fall> is the “coefficient of restitution” of the ball’s rubber. This is the efficiency with which the material returns strain energy as it rebounds. “Internal friction” is a common term for this kind of energy loss. The amount of energy lost by the tire rubber in each rotation is proportional to the amount of flexing, and that in turn is proportional to the weight of the car (for all four wheels combined). This is why rolling resistance is proportional to the car’s weight. These days, many tire companies put additives in the rubber to lower its internal friction.
. . .
Can this be used for non-destruct measurement of relative tire rolling resistance?

Bob Wilson
2019 Std. Range Plus Model 3 - 134 MPG3 || 2014 BMW i3-REx - 117 MPGe, 39 MPG
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