Designation:D4693–03An American National Standard Standard Test Method for
Low-Temperature Torque of Grease-Lubricated Wheel
Bearings1
This standard is issued under thefixed designation D4693;the number immediately following the designation indicates the year of
original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A
superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope*
1.1This test method determines the extent to which a test grease retards the rotation of a specially-manufactured,spring-loaded,automotive-type wheel bearing assembly when sub-jected to low temperatures.Torque values,calculated from restraining-force determinations,are a measure of the viscous resistance of the grease.This test method was developed with greases giving torques of less than35N·m at−40°C.
1.2The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only.
1.3This 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.
2.Referenced Documents
2.1ASTM Standards:2
D217Test Methods for Cone Penetration of Lubricating Grease
D1403Test Method for Cone Penetration of Lubricating Grease Using One-Quarter and One-Half Scale Cone Equipment
D3527Test Method for Life Performance of Automotive Wheel Bearing Grease
D4175Terminology Relating to Petroleum,Petroleum Products,and Lubricants
E1Specification for ASTM Thermometers
E77Test Method for Inspection and Verification of Ther-mometers
E220Test Method for Calibration of Thermocouples by Comparison Techniques
E230Specification and Temperature-Electromotive Force (EMF)Tables for Standardized Thermocouples
E563Practice for Preparation and Use of Freezing Point Reference Baths
E585/E585M Specification for Compacted Mineral-Insulated,Metal-Sheathed,Base-Metal Thermocouple Cable
E608/E608M Specification for Metal-Sheathed Base-Metal Thermocouples
2.2Military Standard:3
MIL-G-10924F Specification for Automotive and Artillery 2.3Other Standard:
Anti-Friction Bearing Manufacturer Assoc.(AFBMA)Stan-dard19,1974(ANSI B.3.19-1975)
3.Terminology
3.1Definitions:
3.1.1automotive wheel bearing grease,n—a lubricating grease specifically formulated to lubricate automotive wheel bearings at relatively high grease temperatures and bearing speeds.D3527 3.1.2lubricant,n—any material interposed between two surfaces that reduces the friction or wear between them.
D4175
3.1.3lubricating grease,n—a semi-fluid to solid product of
a dispersion of a thickener in a liquid lubricant.
3.1.3.1Discussion—The dispersion of the thickener forms a two-phase system and immobilizes the liquid lubricant by surface tension and other physical forces.Other ingredients are commonly included to impact special properties.D217 3.1.4thickener,n—in lubricating grease,a substance com-posed offinely-divided particles dispersed in a liquid lubricant to form the product’s structure.
3.1.
4.1Discussion—The solid thickener can befibers(such as various metallic soaps)or plates or spheres(such as certain non-soap thickeners)which are insoluble or,at the most,only very slightly soluble in the liquid lubricant.The general requirements are that the solid particles be extremely small,
1This test method is under the jurisdiction of Committee D02on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.G0on Lubricating Grease.
Current edition approved Dec.1,2003.Published January2004.Originally approved in1987.Last previous edition approved in2002as D4693–97(2002)e1.
2For referenced ASTM standards,visit the ASTM website,,or contact ASTM Customer S
ervice at For Annual Book of ASTM
Standards volume information,refer to the standard’s Document Summary page on the ASTM website.
3Available from Standardization Documents Order Desk,Bldg.4Section D,700 Robbins Ave.,Philadelphia,PA19111-5094,Attn:NPODS.
1
*A Summary of Changes section appears at the end of this standard.
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uniformly dispered,and capable of forming a relatively stable, gel-like structure with the liquid lubricant.D217 4.Summary of Test Method
4.1A freshly stirred and worked sample of test grease is packed into the bearings of a specially-manufactured, automotive-type spindle-bearings-hub assembly.The assembly is heated and then cold soaked at−40°C,unless another test temperature is specified by the grease specification.The spindle is rotated at1rpm and the torque required to prevent rotation of the hub is measured at60s.
5.Significance and Use
5.1This test method differentiates among greases having distinctly different low-temperature characteristics.This test is used for specification purposes and correlates with its precursor which has been used to predict the performance of greases in automotive wheel bearings in low-temperature service.4It is the responsibility of the user to determine the correlation with other types of service.
6.Apparatus
6.1Low-Temperature Wheel Bearing Torque Apparatus,5 illustrated in Fig.1.
N OTE1—Several apparatus configurations are available,differing mainly in the drive system.For exam
ple,with large cold chambers,a unitized apparatus(see Fig.1)can be used totally within the cold chamber. With small cold chambers,the drive system can be mounted externally and only the test unit subjected to low temperature.Regardless of the exact configuration,the essential apparatus consists of a1/3hp electric motor connected to a gear reducer by means of a timing belt and pulleys,which drive a specially-manufactured spindle-bearings-hub
assembly equipped with a spring-loading mechanism.For apparatus contained totally within the cold chamber,the drive system should be prepared by replacing the grease in the motor bearings with a suitable low-temperature grease(<1N·m torque at−40°C),such as one meeting the requirements of Specification MIL-G-10924F or similar,and the lubricant in the gear reducer should be replaced with a suitable low-temperature(<−50°C pour point)worm-gear lubricant.6In addition,if not already so-equipped, large-diameter(152mm),narrow-width(13mm)timing pulleys and a suitable timing belt should be used.
6.2Torque Measuring System,consisting of a strain-gage load cell with a matching bridge-balance unit,7a suitable strip-chart recorder to record the load-cell output,and a series of weights(up to20kg,at least)suitable for load-cell calibration.
N OTE2—In order to calculate torque from force measurements,the load cell should be located a known distance from the test-unit centerline; 100mm is convenient.A convenient way to do this is to centrally drill a 1.78-mm diameter hole(No.50drill)in the torque arm,100mm from the spindle centerline;temporarily replace the load cell contact with a second contact having a1.59-mm diameter pin(soldered in place)extending about5mm above the contact point;position the load cell to permit insertion of the pin in the torque-arm hole;secure the position of the load cell by tightening the clampin
g screws;replace pin contact with original contact before running test.
6.3Temperature Measuring System,consisting of Type T (preferred)or Type J(acceptable),3.18-mm diameter metal-sheathed,grounded thermocouples meeting Specifications E585/E585M and E608/E608M and conforming to the special limits of error defined in Table1of Specification E230;
a suitable potentiometer,satisfying the requirements for Groups B or C as described in Test Method E220;an ASTM
4Verdura,T.M.,“Performance of Service Station Wheel Bearing Greases in a New Low-Temperature Test,”NLGI Spokesman3510-21(1971).
5Available from Koehler Instrument Co.,1595Sycamore Avenue,Bohemia, L.I.,NY11716.
6Mobil SHC624(or similar),available from Mobil Oil Corporation,3225 Gallows Rd.,Fairfax,V A22037.
7A Model3167-50load cell and matching electronic circuitry are available from Lebow Associates,Inc.,1728Maplelawn,Troy,MI48062.
FIG.1Low-Temperature Torque Apparatus
73C precision thermometer meeting Specification E 1,certified (traceable to National Institute of Standards and Technology certification)or verified and calibrated according to Test Method E 77;a suitable comparator as described in Test Method E 77;and an ice bath prepared according to Practice E 563.
N OTE 3—Other temperature-measuring instrumentation,such as a pre-cision platinum resistance thermometer,may be used instead of thermo-couples,providing the limits of error are within those defined in Specification E 230.
6.4Test Bearing —Use LM67010-LM67048and LM11910-LM11949(AFBMA Standard 19)inboard and outboard ta-pered roller bearings,respectively.8
6.5Low-Temperature Test Chamber ,equipped with internal fan,and capable of maintaining the spindle at −4060.5°C,and with sufficient capacity to cool the spindle at the rate shown in Fig.2(A)and Fig.2(B).
6.6Laboratory Oven ,forced air,capable of maintaining 7063°C.
6.7Grease Packer ,as described in Test Method D 3527or equivalent.
6.8Ultrasonic Cleaner.9
7.Reagents and Materials
7.1Purity of Reagents —Reagent grade chemicals shall be used in all tests.Unless otherwise indicated,it is intended that all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society where such specifications are available.10Other grades may be used,provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2Ethylene Glycol ,commercial automotive antifreeze.(Warning —Moderately toxic.Can be harmful if inhaled,swallowed or absorbed through skin.Contact can irritate eyes,or mucosa.)
7.3Chloroform ,reagent grade.(Warning —Health hazard.)7.41,1,1-Trichloroethane ,reagent grade.(Warning —Health hazard.)
7.4.1For routine testing,a functionally equivalent
pulleyssolvent may be substituted throughout this test method wherever 1,1,1-trichloroethane is specified.However,in referee situa-tions,1,1,1-trichloroethane or chloroform shall be used unless contractual parties agree on the acceptability of the function-ally equivalent solvent.
7.4.1.1To be functionally equivalent,the solvent must not affect test results,must clean as effectively as 1,1,1-trichloroethane,have similar volatility characteristics,leave no residue on evaporation,and contain no water or additives.
N OTE 4—This test method (and the precision values)was originally developed using chloroform.This was subsequently replaced by 1,1,1-trichloroethane which was declared an ozone depleting substance by the U.S.Environmental Protection Agency (EPA).Federal regulations ban the production of this material after December 31,1995,but existing stocks may continue to be used.Currently there are no EPA restrictions on the use of chloroform,but the user should be aware of its health hazards,if it is used.No other solvent intended as a substitute for 1,1,1-trichloroethane in this test method has been cooperatively evaluated.(Warning —If the functionally equivalent solvent is flammable or a health hazard,proper precautions should be taken.)
8.Calibration
8.1Torque Calibration :
8.1.1Place the load cell in the cold chamber at −40°C and allow it to come to temperature equilibrium.Electrically null the load cell and recording potentiometer using the adjusting potentiometer of the matching network.Adjust or standardize the range potentiometer as needed to achieve the desired zero-point and full-scale calibration.Select a millivolt range on the recording potentiometer,and record pen displacement as a known force is applied to the load cell.(It may be necessary to fabricate a platform to attach to the load cell to support the calibrating weights.)Apply several forces (up to about 200N or more)in stepwise fashion while recording pen displacement as a function of applied force.Calibrate the other millivolt ranges in similar fashion until limited by either maximum displacement or maximum load.Remove forces stepwise to determine possible hysteresis.
8.1.2Construct a plot of pen displacement as a function of force for each millivolt range.Use these plots for the subse-quent determination of torque for the test greases.Ordinarily,the plots will be linear,and simple conversion factors can be calculated.
N OTE 5—Data logging software may be uesd to collect this data.
8.1.3This calibration need be done only at the time of initial setup and when occasional checks indicat
e that it is required.However,the torque measuring system is to be standardized before each test.
8.2Temperature Calibration :
8.2.1In order to obtain precise torque measurements,an accurate temperature calibration is essential.Meticulous at-tention to the details described in the several ASTM methods of temperature calibration is of paramount importance.
8.2.2Calibrate the temperature-measuring system,includ-ing both the potentiometer and the spindle thermocouple,at 0°C and −40°C by comparing the observed temperature with that of the certified thermometer as described in Test Method E 220.Alternatively,both thermometer and thermocouple can
8
Timken or Bower bearings are suitable.
9
A Bransonic 220(Branson Cleaning Equipment Co.,Shelton CN 06484),having a capacity of about 4L operating at an output frequency of about 55kHz,with a power input of about 125W,has been found satisfactory.10
Reagent Chemicals,American Chemical Society Specifications ,American Chemical Society,Washington,DC.For suggestions on the testing of reagents not listed by the American Chemical Society,see Analar Standards for Laboratory Chemicals ,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeia and National Formulary ,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.
TABLE 1Torque Test Results at −40°C with NLGI Reference
System A (Batch 3)
Mean value
3.7N·m Standard deviation
0.67N·m Confidence limits,95%:Lower    3.2Upper
4.1
be calibrated using the freezing point of mercury as described in Test Method E 77.The reference ice bath is to be made in accordance with Practice E 563.
N OTE 6—A suitable low-temperature liquid bath can be made with a 65volume per volume percent commercial,automotive-type,ethylene glycol antifreeze (7.2)in water.
8.2.3The temperature correction determined by the thermo-couple calibration shall be applied when measuring the tem-perature of the spindle.8.3Spring Calibration :
8.3.1Remove the spring (Part 8,Fig.3),and outer and inner compression plates (Parts 9and 11,Fig.3)from the test unit.8.3.2Reassemble spring and compression plates in correct order.Apply a force of 400N and measure the distance,60.03
mm,between the compression plates.Since the distance between the plates varies slightly around the circumference of the plates,make the measurement at the point of shortest distance.Mark the spring and both plates to ensure repeatable alignment when assembling the test unit.
8.3.3Using the dimension determined in 8.3.2,construct a custom spring gage of equal length.When assembling the test unit,this gage is to be used to apply a 400N load.
N OTE 7—Some low-temperature torque-test apparatus have been sup-plied with a metal cylinder to be used to calibrate the spring.A small number of these have been found to be incorrect.If an apparatu
s includes such a cylinder,its calibration should be certified by the manufacturer or verified by the test operator before use in this test.The fabrication and use of a custom spring gage is
preferred.
FIG.2(A)Upper and Lower Limits of Cooling Rate and Test
Temperature
FIG.2(B)Detail of Critical Portion of Cooling Rate Curve
(continued)
9.Bearing Preparation
9.1New bearings must be conditioned prior to first use in this method.Install any wheel bearing grease in the bearings and run them at room temperature for 48h at 1000rpm under a thrust load of 110N·m.The apparatus used in Test Method D 3527has been found suitable for conditioning the bearings.Alternatively,other means,such as a drill press,may be employed if the proper speed,load,and duration can be provided.
9.2Remove excess grease from the bearings.Place the bearings in a beaker and cover with 1,1,1-trichl
oroethane (7.3).Place the beaker containing the bearings and solvent in the ultrasonic bath containing distilled water at a depth of about 60mm.After cleaning for 5to 10min,transfer bearings to another solvent-containing beaker and repeat.Repeat as often as necessary (commonly,three times)to clean bearings;use shorter wash times with successive washes.Drain and air dry bearings.
10.Procedure
10.1Clean races of bearing cups,previously installed in the hub,and inspect for nicks or rust spots;replace cups if damaged.Apply a thin film of the test grease to races.
10.2
grease as 10.3Test packer grease with new test grease is not acceptable.
10.4Withdraw the bearing,and with a spatula remove excess grease from the bore and strike off grease flush with both ends of the bearing cone.Remove remaining grease from bore with a lintless cloth or tissue.Remove grease from outer surfaces of rollers and retainer.Care must be exercised to prevent relative rotation of any part of the bearing during this part of the procedure and from this point onward.
10.5Add or remove grease so that the inner and outer bearings contain 3.0and 2.060.1g,respectively.
10.6Install the inner bearing on the spindle,without rotat-ing the rollers and aligning bearing slot with spindle key or pin.Install hub.Install outer bearing on spindle,without rotating rollers and aligning keyway with key.
N OTE 8—Bearings are supplied with keyways or slots,and spindles with corresponding keys or pins,to prevent rotation of the inner races of the bearings during the test.Assembly of the test unit can be facilitated by
FIG.3Test Unit Assembly

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