Designation:G194−08(Reapproved2013)StandardTestMethodforMeasuringRollingFrictionCharacteristicsofaSphericalShapeonaFlatHorizontalPlane1ThisstandardisissuedunderthefixeddesignationG194;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoverstheuseofanangledlaunchramptoinitiaterollingofasphereornearlysphericalshapeonaflathorizontalsurfacetodeterminetherollingfrictioncharacteristicsofagivensphericalshapeonagivensurface.1.1.1Steelballsonasurfaceplatewereusedininterlabo-ratorytests(seeAppendixX1).Golfballsonagreen,soccerandlacrosseballsonplayingsurfaces,bowlingballsonanalane,basketballsonhardwood,andmarblesoncompositesurfaceweretestedinthedevelopmentofthistestmethod,butthetestappliestoanysphererollingonanyflathorizontalsurface.1.1.2Therollingfrictionofspheresonhorizontalsurfacesisaffectedbythesphericalshape’sstiffness,radiusofcurvature,surfacetexture,filmsonthesurface,thenatureofthecounter-facesurface;therearemanyfactorstoconsider.Thistestmethodtakesallofthesefactorsintoconsideration.Thesphericalshapeofinterestisrolledonthesurfaceofinterestusingastandardramptoinitiaterollingandstandardtech-niquestomeasureandtreattherolleddistanceafterleavingtheramp.1.1.3Thistestmethodproducesarollingresistancenumberonaspecificsphericalshapeonaspecificsurface.Itisintendedforcomparingsimilartribosystems.Forexample,therollingresistancesofmarblesonaparticularsurfacearenottobecomparedwiththerollingresistanceofsoccerballsongrass,becausetheirmassesanddiametersareverydifferentasarethecounterfacesurfacesonwhichtheyroll.1.1.4Differentlaunchrampsforareappropriatefordifferenttypesofsphericalshapes.IfasphereofinterestcannotbeaccommodatedwithusingoneofthelaunchrampsdiscussedinAppendixX1andAppendixX2,adifferentlaunchrampcanbedevelopedandaddedwithfuturerevisionstothistest...
