ASTM_F_457_-_04_2010.pdf

Designation:F45704(Reapproved 2010)Standard Test Method forSpeed and Distance Calibration of Fifth Wheel EquippedWith Either Analog or Digital Instrumentation1This standard is issued under the fixed designation F457;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of vehiclespeed and cumulative distance traveled using a device termeda fifth wheel and using appropriate associated instrumentation.1.2 This test method also describes the calibration techniqueapplicable to digital or analog speed and distance measurementsystems employing a fifth wheel.1.3 The values stated in SI(millimetre-kilogram)units areto be regarded as the standard.1.4 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.For specificprecautionary statements,see Section 7.2.Referenced Documents2.1 ASTM Standards:2F538 Terminology Relating to the Characteristics and Per-formance of TiresF1082 Practice for TiresDetermining Precision for TestMethod Standards(Withdrawn 2005)33.Terminology3.1 Refer to Terminology F538.4.Summary of Test Method4.1 Vehicle speed and distance determinations are made byuse of a fifth wheel,signal transducer(s),and compatibledisplay devices.4.2 The fifth wheel assembly and signal transducer(s)areattached to the vehicle or the test trailer so that the fifth wheelremains in contact with the normal roadway surface while theequipment is in motion.The rotation of this wheel is detectedin a suitable manner and is translated into measurements ofvehicle speed and distance with auxiliary equipment.4.3 The speed is to be communicated to the vehicle operatorat all times,and should be visible without undue distraction ora requirement for physical movement on the part of theoperator.4.4 Fifth wheel calibration is performed by operating thedevice at a fixed speed over a known distance and comparingthe speed and distance readout to a known speed and distance.5.Significance and Use5.1 This test method may be used for calibration of speedand distance measurement systems used on tire test vehiclesand tire test trailers,or any land-based vehicle that contacts theroad and that uses a trailing-wheel system for measurement ofspeed and distance.This test method applies only to hard,dry,smooth surfaces and is not accurate for highly curved vehiclepaths.This test method does not encompass optical types ofdevices.6.Apparatus6.1 Fifth WheelThe fifth-wheel assembly shall be ofsufficient mechanical integrity to withstand long periods ofsustained operation with minimal maintenance.The wheelvertical pivot assembly shall be sufficient to permit directionalchanges without inducing lateral skidding of the fifth-wheeltire.The fifth-wheel assembly shall be equipped with asuspension capable of minimizing bounce and wheel hop,dueto roadway irregularities,to the extent necessary to ensuremeasurement accuracy.The wheel shall be equipped with asuitable tire,preferably of a straight-ribbed design.The tiresshall have a minimum(new)size of 34937(16 138).Tireand wheel shall be balanced statically each time the tire isreplaced.6.2 InstrumentationFifth-wheel systems shall be equippedwith either analog or digital instrumentation for determiningwheel rotation.Suitable readouts shall be provided.6.2.1 Analog Instrumentation:1This test method is under the jurisdiction of ASTM Committee F09 on Tiresand is the direct responsibility of Subcommittee F09.10 on Equipment,Facilitiesand Calibration.Current edition approved Feb.1,2010.Published May 2010.Originallyapproved in 1976.Last previous edition approved in 2004 as F457 04.DOI:10.1520/F0457-04R10.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2.1.1 Generator(tachometer)The generator shall becoupled to the fifth wheel to produce an electrical outputproportional to the angular velocity(converted into linearvelocity expressed in km/h(mph)of the fifth wheel.Thegenerator output shall be continuously proportional to therotational velocity within the required tolerance.The generatoroutput shall be biased after engineering unit conversion by anamount less than or equal to 0.5%of the converted speed,or0.3 km/h(0.2 mph),whichever is greater.The