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Old 05-06-2009, 11:46 AM   #44 (permalink)
Ernie Rogers
Ernie Rogers
 
Join Date: Feb 2008
Location: Pleasant Grove, Utah
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Deflection is determined by air pressure only

Hello, Clark,

You are missing something. The deflection of the tire is only related to the tire pressure. Another way of saying it: the contact patch area is the same size whether the rubber is hard or soft.

It takes more energy to deflect hard rubber by a specified amount. That's why soft rubber works better.

Most of us have noticed a decrease in fuel economy in winter. One explanation for that is that the tire rubber gets harder when cold.

Ernie

Quote:
Originally Posted by ConnClark View Post
Regardless of what the load bearing material is be it air, hard rubber, steel, or even stone, the softer rubber still is caught between it and the ground. It still will be compressed and create rolling resistance by increasing the contact patch area.

Lets take the the tire flex out of the equation entirely. Roll a large ball bearing on a large sheet of soft rubber and a large sheet of hard rubber. The soft sheet of rubber will induce a higher rolling resistance on the ball bearing.
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