This SAE Recommended Practice applies to the laboratory
measurement of rolling resistance of pneumatic passenger car, light
truck, and highway truck and bus tires. The procedure applies only
to the steady-state operation of free-rolling tires at zero slip
and inclination angles; it includes the following three basic
Force Method--Measures the reaction force at the tire spindle and converts it to rolling resistance.
Torque Method--Measures the torque input to the test machine and converts it to rolling resistance.
Power Method--Measures the power input to the test machine and converts it to rolling resistance.