When a cylindrical object such as a wheel rolls on a surface, the force resisting motion is rolling friction.
Rolling friction can be computed as follows:
- Let WeightLbs be the total weight of the wheel including any load
- Let CRF be the coefficient of rolling friction in inches for the involved materials
- RollingFrictionLbs = WeightLbs * CRF / WheelRadiusInch
The coefficient of rolling friction is not the same as sliding coefficient of friction. Tables of coefficients of rolling friction are inconsistent however the following may be used as ballpark values (inch):
- Wood on Wood – 0.06
- Iron on Iron – 0.02
- Iron on Wood – 0.22
- Hardened steel ball bearings on steel – 0.004
- BMX bicycle tire – 0.0055
- Car tire on concrete – 0.010 to 0.015
- Car tire on tar or asphalt – 0.030 to 0.035
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