ASTM E556/E556M-11

Wheel force or torque transducers are used under dynamic test conditions, and the measurements are subject to many error sources. The static calibration recommended by the present standard cannot eliminate all error sources. Its significance is in providing an accurate calibration of the transducer and the associated electronics, readout, and recording equipment.

Calibration result may be used to either make mechanical or electronic adjustments until the readout agrees with the calibration input. Alternatively, calibration curves or tables may be prepared to be used as corrections to measured results.

1.1 This test method covers the calibration of the force (or torque) transducer and associated instrumentation of a mounted test wheel by using a calibration platform.

1.2 This test method is a static calibration, simulating the traction force between a tire and the pavement.

1.3 In the case of a force-measuring system, the instrumentation readout is directly proportional to the calibration force input.

1.4 In the case of a torque-measuring system, the instrumentation readout is a measure of the calibration force input and the effective tire radius.

1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.