1、Designation: F538 13Standard Terminology Relating to theCharacteristics and Performance of Tires1This standard is issued under the fixed designation F538; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology primarily covers definitions for tech-nical terms that occur in ASTM Committee F09 standards onthe characteristics an
3、d performance of tires.1.2 Definitions for terms that may also be used in othertechnologies, such as vehicle behavior, are worded to coverboth areas.1.3 When any definition in this terminology (that does nothave the limiting phrase) is quoted out of context, editoriallyinsert the limiting phrase in
4、a tire after the dash following theterm. This will properly limit the field of application of theterm and definition.2. Terminology2.1 Definitions:accelerometer, nan instrument that senses inertial reaction tomeasure linear or angular acceleration. F811accuracy, na measurement concept that describes
5、 the degreeof correspondence between an average measured value andan accepted reference or standard value for the object,material or phenomenon under test. F1082age, vto apply conditions so as to promote change of materialproperties. F2838aging, accelerated laboratory (also: aging, laboratory),nincr
6、eased rate of tire material property changes underspecified conditions, including temperature, inflationpressure, oxygen concentration in the filling gas, and time.F2838aging, in-service, nmaterial property changes within tiresdue to consumer usage. F2838aging, oven, naccelerated laboratory aging in
7、 an elevatedtemperature environment. F2838aging, thermal oxidative, nthe process whereby chemicaland physical material properties of a tire change withexposure to heat and oxygen. F2838aligning stiffness FL/, nof a tire, the rate of change of tirealigning torque with respect to change in tire slip a
8、ngle,usually evaluated at zero slip angle.aligning stiffness coefficient, nof a tire, the ratio of tirealigning stiffness to the tire normal force.aligning torque FL, nof a tire, the component of a tiremoment vector tending to rotate a tire about the Z-axis,positive clockwise when looking in the pos
9、itive direction ofthe Z-axis. F403, F424alignment, nthe adjustment of various parts of the vehiclessuspension system to ensure proper handling stability and tominimize abnormal tire treadwear. F1922all-season tread, ntread design providing dry, wet, and snowtraction performance for an optimized bala
10、nce for year-round performance and which may meet the Rubber Manu-facturers Association (RMA) definition for an M specific limitsnormally apply. F8111This terminology is under the jurisdiction of ASTM Committee F09 on Tiresand is the direct responsibility of Subcommittee F09.94 on Terminology.Curren
11、t edition approved June 1, 2013. Published June 2013. Originallyapproved in 1977. Last previous edition approved in 2009 as F538 09. DOI:10.1520/F0538-13.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1bead, nof a tire, the part of a
12、tire that comes in contact withthe rim and is shaped to secure the tire to the rim. F1922,F1923, F2663bead separation, na breakdown of bond between tirecomponents in the bead area. F1922bead unseating block, nmachined block of cast aluminum(also known as “shoe”) used on the bead unseating fixture to
13、press against the tire sidewall. F2663belt, nin a tire, a breaker that substantially restricts thecarcass in a circumferential direction. F1922, F1923belt edge (BE) temperature, nin the cross section of a radialtire, the temperature at the edge of the stabilizer plies orbelts, for example, in the ru
14、bber region of the two belt edges.F2779, F2869belt separation, na breakdown of bonding between the beltsor plies or tread, or combination thereof. F1922bias, nthe difference between the average measured testresult and the accepted reference value; it measures in aninverse manner the accuracy of a te
15、st. F1082black sidewall, na sidewall on which only black compoundscomprise the outer visible surface of the tire. F724block, nsynonym for element. F1426bottom out, vto deform a tire by radial load on the tread untilradial movement of the inside surface is stopped by the rimor other tire inside surfa
16、ce. F414braking coefficient nd, nthe ratio of the braking force tothe normal force on a tire.braking force F, nof a tire, the negative longitudinal forceresulting from braking torque application. F403, F408braking force coefficient, nof a tire, the ratio of brakingforce to normal force. F403, F408br
17、aking force coefficient, peak, nof a tire, the maximumvalue of tire braking force coefficient that occurs prior towheel lockup as the braking torque is progressively in-creased. F403, F408braking force coefficient, slide, nof a tire, the value ofbraking force coefficient obtained on a locked wheel.
18、F 403,F408braking torque ML2/T2,nof a vehicle, the negative wheeltorque. F403, F408brand, nof a tire, the name under which one or more tirelines are marketed.brand, tire, private, na brand name used by a tire seller orgroup of sellers who are not manufacturers.break, na crack or tear extending into
19、or through thereinforcing material. F1922breaker, nin a tire, one or more plies under the tread regionof a tire that are additional to those which extend from beadto bead.break-in L,none or more periods of initial standardizedtire operation during which tire is brought to the state whichwill lead to
20、 more consistent test results. F762, F1016calibration tire, na witness tire designed to provide a fixedor known test value for selected properties. F1806candidate tire, na test tire that is part of a test program.F1572, F1649, F1650, F1805, F1806, F1922candidate tire set, na set of candidate tires.
21、F1572, F1649,F1805, F1806caravan, nfor purposes of a tire test, two or more vehiclesrunning in the same time frame, over the same test course(s),under similar but independent conditions. F1922carcass, nof a tire, the part of a tire structure that does notinclude the tread and sidewall rubber.casing,
22、 nof a tire, a used or treadless tire to which additionaltread rubber may be attached for the purpose of retreading.F1922center of tire contact, nthe intersection of the wheel planeand the vertical projection of the spin axis of a wheel ontothe road plane.center rib, na rib at or near the circumfere
23、ntial centerline ofthe tread band. F1426center row, na row located at or near the circumferentialcenterline. F1426center wear, na type of irregular wear characterized by awear rate continuously increasing from shoulder to center ofthe tread band. F1426centripetal acceleration ML2/T2,nof a vehicle, t
24、hecomponent of the vector acceleration (of a point in a vehicle)perpendicular to the tangent of the path of the point andparallel to the road plane.chip and tear, na special type of irregular wear characterizedby a rough tread surface which may contain cracks, abrasionpits or surface ruptures. F1426
25、circumferential line, non a tire, any real or imaginary circleon the surface of a tire, lying in a plane that is perpendicularto the spin axis. F421, F870clinch strip, nhigh-modulus or high-hardness compoundapplied between the carcass and the sidewall in the bead areato reinforce the bead. F724cold
26、inflation pressure, nthe gauge pressure of a tire,measured after equilibration at ambient temperature. F2838connection point, nany point on the wheel or metal loadingplate where the resistance measuring instruments leads areconnected. F1971contained air temperature, nthe temperature of the aircontai
27、ned within the tire cavity when the tire is mounted andinflated on the proper rim. F2779, F2869F538 132control tire, na reference tire, used in a specified mannerthroughout a test program F1572, F1649, F1805, F1806,F1922convoy, nin tire testing, two or more vehicles running at thesame time, over the
28、 same test course, under the sameinterdependent conditions. F1922cord, nin a tire, filament(s) or plied yarns used in making atire ply. F1922cornering force ML2/T2,nof a tire, the horizontal forceacting perpendicularly to the instantaneous motion vector ofthe center of contact for a tire operating a
29、t a slip angle.cornering force coefficient nd, nthe ratio of corneringforce to the normal force on a tire.cornering stiffness F/, nof a tire, the negative of the rateof change of tire lateral force with respect to change in tireslip angle, usually evaluated at zero slip angle.cornering stiffness coe
30、fficient, nof a tire, the ratio of tirecornering stiffness to tire normal force.cornering traction coefficient, nthe ratio of the corneringtractive force vector and normal force.cornering traction vector angle, nthe angle between theresultant cornering traction force vector and the X axis.cornering
31、tractive force, (F), nthe vectorial sum of lateraland longitudinal tractive force components.coverstrip, na thin layer of black compound which coversthe unexposed white sidewall portion of a finished tire. F724crazing, nminute, closely grouped, generally superficialcracks that usually results from l
32、ight activated oxidation.F724critical slip angle, (rad or degree), nthe value of the slipangle at the peak lateral force coefficient.cross-country track, nsurface not subject to repeated trafficin addition, no roads, routes, well-worn trails or man-madeimprovements; can consist of tank trails with c
33、rushed rock orhaving large exposed obstacles (rocks, boulders, etc.). F1922cupping, na type of irregular wear characterized by avariation in wear rate that may be periodic (essentiallycycloidally shaped) around the tread band circumference inone or more rows; the variation of loss is essentiallyinde
34、pendent of individual projections if the pattern containsthese projections. F1426curved equivalent test severityin tire testing, the testconditions (load, rotational speed, tire inflation pressure) onthe flat or highway surface that will provide equivalentinternal tire temperatures, for example, at
35、the belt edge, to aknown set of curved 1.707-m roadwheel surface testconditions. F2779, F2869determination, nthe application of the complete measure-ment procedure to one piece, specimen or object to produceone numerical measured value to be used to form an averageor median. F1082developed footprint
36、 length L, nthe maximum footprintdimension in the circumferential direction of the tire, understated conditions of measurement. F870developed footprint width L, nthe maximum lateral di-mension of a tire footprint under stated conditions ofmeasurement. F870diagonal wear, na type of irregular wear cha
37、racterized by anincreased wear rate region or band oriented transversely(from shoulder to shoulder) at some non-90 angle withrespect to the circumferential centerline of the tread band.F1426driving coefficient nd, nthe ratio of the driving force to thenormal force. F424, F1572, F1805driving coeffici
38、ent, peaknd, nthe maximum value of thedriving coefficient. F424driving force, F, nof a tire, the positive longitudinal forceresulting from the application of driving torque. F424,F1572, F1805driving torque ML2/T2,nof a wheel, the positive wheeltorque. F424effective rolling radius, nthe ratio of the
39、linear velocity ofthe wheel center of the free rolling tire in the X direction tothe spin velocity. F424element, nan isolated (totally bounded by void) projection.F421, F762, F870, F1426endurance, nof a tire, the ability of a tire to perform asdesigned in its intended usage conditions such as load,i
40、nflation pressure, speed, time, and environmentalconditions. F2779, F2869fastest wearing groove L, nthe circumferential groovewith the minimum life expectancy. F1016fastest wearing location L, nthat location which exhibitsthe highest percent tread (depth) loss (as calculated in 6.1.1of Practice F101
41、6). F1016feathering, na type of element irregular wear characterizedby thin strips of rubber extending from the edge of theelement. F1426flange, nthat part of the rim which gives lateral support to thetire.flex cracking, ncracking primarily caused by application ofmechanical stress-strain cycling. F
42、724footprint area L2, nthe gross contact area of a tire that isloaded (under stated conditions) against a smooth flatsurface. F870free rolling tire, na loaded tire rolling without applieddriving or braking torque. F424F538 133front end breakaway, nin cornering vehicle, the point in thecurved traject
43、ory of a vehicle when it can no longer bemaintained on its intended path because of front wheeldeparture toward the outside of the curve.g, na unit of acceleration where 1 g is equal to theacceleration of gravity, 9.8 m/s2(32.2 ft/s2). F811global testing, ntesting conducted at two or more laborato-r
44、ies or test sites for the purpose of comparing candidate tireperformance at each location for selected characteristicproperties. E1806gravel road, ntwo lane, all-weather, occasionallymaintained, hard or loose surface (for example, large rock,paved, crushed rock, gravel) intended for medium-weight,lo
45、w-density traffic, in accordance with the U.S. FederalHighway Administration. F1922grooming, vin tire testing, mechanically reworking a snowtest surface in order to obtain a surface with more consistentproperties. F1572, F1805groove, na void that is relatively narrow compared to itslength. F414, F42
46、1, F762, F870, F1046, F1426, F1922,F1923groove, average depth L, nthe average of all tire groovedepth measurements in a single groove.F421, F762, F1016, F1046groove (void) area L2, nthat portion of tire footprint areawhich is not contacted by ribs or elements. F762, F870groove (void) area fraction n
47、d, nthe ratio of the groove(void) area to the footprint area of a tire. F870groove (void) depth L, na measurement of the perpendicu-lar distance from a real or calculated reference plane definedby edges of two adjacent ribs (lugs) to the lowest point ofcontact in the groove (void). F421, F762, F1046
48、, F1922,F1923gyro-stabilized accelerometer, na precision vertical gyro-scope fitted with one to three accelerometers to provideorthogonal measurements referenced to the earth-fixed axissystem. F811heel-toe wear, na type of irregular wear characterized bydifferent wear rates at the leading and traili
49、ng edges of aprojection (element). F1426high speed performance, nof a tire, the rotational speedcapability of a tire to perform as designed in its intendedusage conditions such as load, inflation pressure, speed,time, and environmental conditions. F2779, F2869highway equivalent test severityin tire testing, the testconditions (load, rotational speed, tire inflation pressure) onthe 1.707-m roadwheel that will provide equivalent inter
