G194 (version 25)

1.1 This test method covers the use of an angled launch ramp to initiate rolling of a sphere or nearly spherical shape, referred to as the specimen throughout this document, on a flat horizontal plane, referred to as the rolling surface, to determine the rolling friction characteristics of a given spherical shape on a given surface.

1.1.1 Steel balls on a surface plate were used in interlaboratory tests (see Appendix X1). Golf balls on a green, soccer and lacrosse balls on playing surfaces, bowling balls on a lane, basketballs on hardwood, and marbles on a composite surface were tested in the development of this test method, but the test applies to any specimen rolling on any rolling surface.

1.1.2 The rolling friction of specimens on rolling surfaces is affected by many factors, including specimen’s stiffness, radius of curvature, surface texture, the presence of films on the surface, and the nature of the rolling surface. This test method takes all of these factors into consideration. The specimen of interest is rolled on the rolling surface of interest using a standard ramp to initiate rolling and standard techniques are used to measure and treat the rolled distance after leaving the ramp.

1.1.3 This test method produces a rolling resistance number for a specific specimen on a specific rolling surface. It is intended for comparing similar tribosystems. For example, the rolling resistances of marbles on a particular surface are not to be compared with the rolling resistance of soccer balls on grass, because their masses and diameters are very different as are the rolling surfaces on which they roll.

1.1.4 Different launch ramps are appropriate for different types of specimens. If a specimen of interest cannot be accommodated with using one of the launch ramps discussed in Appendix X1 and Appendix X2, a different launch ramp can be developed and added with future revisions to this test method.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.