scope:

This method covers the calibration of the force (or torque) transducer and associated instrumentation of a mounted test wheel by using a calibration platform. It is used for establishing correction factors for changes in transducer output due to changes in operating conditions.

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

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

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

This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.