ASTM_F_2273_-_11.pdf

Designation:F227311An American National StandardStandard Test Methods forBicycle Forks1This standard is issued under the fixed designation F2273;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods describe mechanical tests for deter-mining the following performance properties:1.1.1 Compression Load,1.1.2 Bending Load,1.1.3 Impact Resistance,and1.1.4 Bending Fatigue Life(followed by Impact Resis-tance).1.2 The values stated in SI units are to be regarded asstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesF2043 Classification for Bicycle Usage3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 bicycle fork(fork)the mechanism between the headtube and the front axle,including the steerer tube,crown(s),shock absorbers,lower tubes,and upper tubes.3.1.2 steer tubethe structural fork component typicallyhoused inside the bicycle head tube,connected to the forkcrown.The steerer tube transmits steering inputs from the riderto the fork and connects the fork to the bicycle frame by meansof headset bearings.3.1.3 fork crown(s),or crown(s)the primary structuralfork component responsible for connecting the steerer tube tothe fork upper tube(s)or fork blades.Some suspension forkshave an upper and a lower crown,while other forks have onlyone.3.1.4 dropoutthe fork component used to support the frontwheel(s)at the axle(s).3.1.5 dropout centerlinethe front hub mounting axis thatpasses through both right and left dropouts.3.1.6 tire clearancethe distance between the top surfaceof the tire and the bottom surface of the fork crown with nocompressive force applied to the fork.3.1.7 crown-to-axle clearancethe distance between thefork axle centerline and the bottom surface of the crown withno compressive load applied to the fork.3.1.8 head setthe bearing cup,cones,and other supportingcomponents for allowing rotation of the fork about the steeringaxis.3.1.9 limit trip or stopa deflection of the fork,whichexceeds the allowable displacement values and causes themachine to stop running.3.1.10 suspension forkfront fork incorporating compli-ance in the axial direction,parallel to the steer tube.3.1.11 rigid forkfront fork that is not designed to becompliant in the axial direction.4.Summary of Test Methods4.1 Compression Load TestIn this test the fork is com-pressed in a direction parallel to the steerer tube.The distancefrom the bottom surface of the crown to the axle centerline ismeasured.4.2 Bending Load TestIn this test the fork is restrained bythe steerer tube and a load is applied in a direction perpendicu-lar to the steerer tube axis,at the midpoint of the dropoutcenterline.The deflection is measured at the dropout centerlinein a direction perpendicular to the steerer tube axis.4.3 Impact Resistance TestIn this test a fork is fixturedwith the steerer tube oriented horizontally,and supported bybearings.A weight is dropped from a prescribed height onto afixture attached to the fork dropouts in line with the dropoutcenterline.Permanent deflection is measured at the dropoutcenterline in a direction perpendicular to the steerer tube axis.The ability of the connection between the steerer tube and1These test methods are under the jurisdiction of ASTM Committee F08 onSports Equipment,Playing Surfaces,and Facilitiesand is the direct responsibility ofSubcommittee F08.10 on Bicycles.Current edition approved March 1,2011.Published June 2011.Originallyapproved in 2003.Last previous edition approved in 2003 as F2273 03.DOI:10.1520/F2273-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 crown to support torque applied about the axis of the steerertube is also evaluated.4.4 Fatigue Plus Impact TestIn this test a fork is restrainedby the steerer tube and a fully reversed load is applied in adirection perpendicular to the steerer tube axis at the midpointof the dropout centerline.The test is suspended and the sampleinspected if displacements exceed a prescribed value,or afterthe specified number of cycles,whichever comes first.If thetest sample reaches the target cycle count,it is subsequentlysubjected to a frontal impact as described in 4.3.If