1、Designation: F 538 09Standard Terminology Relating to theCharacteristics and Performance of Tires1This standard is issued under the fixed designation F 538; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 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 This terminology primarily covers definitions for tech-nical terms that occur in ASTM Committee F09 standards onthe characteristics
3、and 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 i
4、n 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 reactionto measure linear or angular acceleration. F811accuracy, na measurement concept that describ
5、es the degreeof correspondence between an average measured value andan accepted reference or standard value for the object,material or phenomenon under test. F 1082aligning stiffness FL/g, nof a tire, the rate of change of tirealigning torque with respect to change in tire slip angle,usually evaluat
6、ed 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 Z8-axis,positive clockwise when looking in the positive direction oft
7、he Z8-axis. F 403, F 424alignment, nthe adjustment of various parts of the vehiclessuspension system to ensure proper handling stability and tominimize abnormal tire treadwear. F 1922all-season tread, ntread design providing dry, wet, and snowtraction performance for an optimized balance for year-ro
8、und performance and which may meet the Rubber Manu-facturers Association (RMA) definition for an M specific limitsnormally apply. F811bead, nof a tire, the part of a tire that comes in contact withthe rim and is shaped to secure the tire to the rim. F 1922,F 1923, F 2663bead separation, na breakdown
9、 of bond between tirecomponents in the bead area. F 1922bead unseating block, nmachined block of cast aluminum(also known as “shoe”) used on the bead unseating fixture topress against the tire sidewall. F 2663belt, nin a tire, a breaker that substantially restricts thecarcass in a circumferential di
10、rection. F 1922, F 1923belt separation, na breakdown of bonding between the beltsor plies or tread, or combination thereof. F 1922bias, nthe difference between the average measured testresult and the accepted reference value; it measures in aninverse manner the accuracy of a test. F 1082black sidewa
11、ll, na sidewall on which only black compoundscomprise the outer visible surface of the tire. F 724block, nsynonym for element. F 1426bottom out, vto deform a tire by radial load on the treaduntil radial movement of the inside surface is stopped by the1This terminology is under the jurisdiction of AS
12、TM Committee F09 on Tiresand is the direct responsibility of Subcommittee F09.94 on Terminology.Current edition approved June 15, 2009. Published July 2009. Originallyapproved in 1977. Last previous edition approved in 2003 as F 538 03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C70
13、0, West Conshohocken, PA 19428-2959, United States.rim or other tire inside surface. F 414braking 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. F 403, F 408braking fo
14、rce coefficient, nof a tire, the ratio of brakingforce to normal force. F 403, F 408braking 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. F 403, F 408braking force coefficien
15、t, slide, nof a tire, the value ofbraking force coefficient obtained on a locked wheel.F 403, F 408braking torque ML2/T2, nof a vehicle, the negative wheeltorque. F 403, F 408brand, nof a tire, the name under which one or more tirelines are marketed.brand, tire, private, na brand name used by a tire
16、 seller orgroup of sellers who are not manufacturers.break, na crack or tear extending into or through thereinforcing material. F 1922breaker, 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
17、initial standardizedtire operation during which tire is brought to the state whichwill lead to more consistent test results. F 762, F 1016calibration tire, na witness tire designed to provide a fixedor known test value for selected properties. F 1806candidate tire, na test tire that is part of a tes
18、t program.F 1572, F 1649, F 1650, F 1805, F 1806, F 1922candidate tire set, na set of candidate tires. F 1572,F 1649, F 1805, F 1806caravan, 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. F 1922
19、carcass, nof a tire, the part of a tire structure that does notinclude the tread and sidewall rubber.casing, nof a tire, a used or treadless tire to which additionaltread rubber may be attached for the purpose of retreading.F 1922center of tire contact, nthe intersection of the wheel planeand the ve
20、rtical projection of the spin axis of a wheel ontothe road plane.center rib, na rib at or near the circumferential centerline ofthe tread band. F 1426center row, na row located at or near the circumferentialcenterline. F 1426center wear, na type of irregular wear characterized by awear rate continuo
21、usly increasing from shoulder to center ofthe tread band. F 1426centripetal acceleration ML2/T2, nof a vehicle, the com-ponent 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 irr
22、egular wear character-ized by a rough tread surface which may contain cracks,abrasion pits or surface ruptures. F 1426circumferential line, non a tire, any real or imaginary circleon the surface of a tire, lying in a plane that is perpendicularto the spin axis. F 421, F 870clinch strip, nhigh-modulu
23、s or high-hardness compoundapplied between the carcass and the sidewall in the bead areato reinforce the bead. F 724connection point, nany point on the wheel or metal loadingplate where the resistance measuring instruments leads areconnected. F 1971control tire, na reference tire, used in a specifie
24、d mannerthroughout a test program F 1572, F 1649, F 1805,F 1806, F 1922convoy, nin tire testing, two or more vehicles running at thesame time, over the same test course, under the sameinterdependent conditions. F 1922cord, nin a tire, filament(s) or plied yarns used in making atire ply. F 1922corner
25、ing force ML2/T2, nof a tire, the horizontal forceacting perpendicularly to the instantaneous motion vector ofthe center of contact for a tire operating at a slip angle.cornering force coefficient nd, nthe ratio of corneringforce to the normal force on a tire.cornering stiffness F/g, nof a tire, the
26、 negative of the rateof change of tire lateral force with respect to change in tireslip angle, usually evaluated at zero slip angle.cornering stiffness coefficient, nof a tire, the ratio of tirecornering stiffness to tire normal force.cornering traction coefficient, nthe ratio of the corneringtracti
27、ve force vector and normal force.cornering traction vector angle, nthe angle between theresultant cornering traction force vector and the X8 axis.cornering tractive force, (F), nthe vectorial sum of lateraland longitudinal tractive force components.coverstrip, na thin layer of black compound which c
28、oversthe unexposed white sidewall portion of a finished tire.F 724crazing, nminute, closely grouped, generally superficialcracks that usually results from light activated oxidation.F 724critical slip angle, (rad or degree), nthe value of the slipangle at the peak lateral force coefficient.cross-coun
29、try track, nsurface not subject to repeated trafficin addition, no roads, routes, well-worn trails or man-madeimprovements; can consist of tank trails with crushed rock orhaving large exposed obstacles (rocks, boulders, etc.).F 1922cupping, na type of irregular wear characterized by avariation in we
30、ar rate that may be periodic (essentiallycycloidally shaped) around the tread band circumference inone or more rows; the variation of loss is essentiallyindependent of individual projections if the pattern containsthese projections. F 1426determination, nthe application of the complete measure-ment
31、procedure to one piece, specimen or object to produceone numerical measured value to be used to form an averageor median. F 1082developed footprint length L, nthe maximum footprintF538092dimension in the circumferential direction of the tire, understated conditions of measurement. F 870developed foo
32、tprint width L, nthe maximum lateraldimension of a tire footprint under stated conditions ofmeasurement. F 870diagonal wear, na type of irregular wear characterized by anincreased wear rate region or band oriented transversely(from shoulder to shoulder) at some non-90 angle withrespect to the circum
33、ferential centerline of the tread band.F 1426driving coefficient nd, nthe ratio of the driving force to thenormal force. F 424, F 1572, F 1805driving coefficient, peaknd, nthe maximum value of thedriving coefficient. F 424driving force, F, nof a tire, the positive longitudinal forceresulting from th
34、e application of driving torque. F 424,F 1572, F 1805driving torque ML2/T2, nof a wheel, the positive wheeltorque. F 424effective rolling radius, nthe ratio of the linear velocity ofthe wheel center of the free rolling tire in the X8 direction tothe spin velocity. F 424element, nan isolated (totally
35、 bounded by void) projection.F 421, F 762, F 870, F 1426fastest wearing groove L, nthe circumferential groovewith the minimum life expectancy. F 1016fastest wearing location L, nthat location which exhibitsthe highest percent tread (depth) loss (as calculated in 6.1.1of Practice F 1016). F 1016feath
36、ering, na type of element irregular wear characterizedby thin strips of rubber extending from the edge of theelement. F 1426flange, nthat part of the rim which gives lateral support tothe tire.flex cracking, ncracking primarily caused by application ofmechanical stress-strain cycling. F 724footprint
37、 area L2, nthe gross contact area of a tire that isloaded (under stated conditions) against a smooth flatsurface. F 870free rolling tire, na loaded tire rolling without applieddriving or braking torque. F 424front end breakaway, nin cornering vehicle, the point in thecurved trajectory of a vehicle w
38、hen 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-ries or test sites
39、for the purpose of comparing candidate tireperformance at each location for selected characteristicproperties. E 1806gravel road, ntwo lane, all-weather, occasionally main-tained, hard or loose surface (for example, large rock, paved,crushed rock, gravel) intended for medium-weight, low-density traf
40、fic, in accordance with the U.S. Federal HighwayAdministration. F 1922grooming, vin tire testing, mechanically reworking a snowtest surface in order to obtain a surface with more consistentproperties. F 1572, F 1805groove, na void that is relatively narrow compared to itslength. F 414, F 421, F 762,
41、 F 870, F 1046, F1426,F 1922, F 1923groove, average depth L, nthe average of all tire groovedepth measurements in a single groove.F 421, F 762, F 1016, F 1046groove (void) area L2, nthat portion of tire footprint areawhich is not contacted by ribs or elements. F 762, F 870groove (void) area fraction
42、 nd, nthe ratio of the groove(void) area to the footprint area of a tire. F 870groove (void) depth L, na measurement of the perpen-dicular distance from a real or calculated reference planedefined by edges of two adjacent ribs (lugs) to the lowestpoint of contact in the groove (void). F 421, F 762,F
43、 1046, F 1922, F 1923gyro-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 an
44、d trailing edges of aprojection (element). F 1426ice, dry, nsmooth ice without loose surface materials.F 1572, F 1805inclination angle, nof a tire, the angle between the Z8-axisand the wheel plane. F 424inflation pressure loss rate, nrate of change of normalizedinflation pressure, determined from th
45、e slope of the linearportion of the log pressure versus time curve. F 1112inner liner, nof a tire, the innermost layer(s) of a tubelesstire that limit(s) diffusion of the inflation medium into thecarcass.intended trajectory, nthe intended or ideal path (rectilinearor curvilinear) to bring a vehicle
46、to a stop, that is, undercontrolled angular orientation. F 1649intermediate rib, none or more rib(s) located between thecenterline and the shoulder ribs of the tread band. F 1426intermediate row, na row located between the circumfer-ential centerline and the shoulder ribs/rows of the tread band.F 14
47、26inter-projection wear, na type of irregular treadwear char-acterized by different wear rates on one or more adjacentprojections (either transverse or circumferential orientation);this results in a step-off in tread depth between the adjacentprojections. F 1426intra-projection wear, na type of irre
48、gular wear character-ized by a different wear rate at two or more locations withina given projection. F 1426inverse wear rate nd, nthe distance traveled by a tire, afterbreak-in, per unit loss in tread depth. F 1016irregular wear, na type of treadwear characterized bysubstantial variations of tread
49、loss both from projection toprojection and frequently from point to point on a givenprojection. F 421, F 762, F 1426juncture, nthe interface between two different tire compo-nents or different compounds within the same component.F 724F538093juncture cracking, na crack with opening originating at ajuncture between two components. F 724juncture opening, na separation developing in a juncture.F 724kerf, nsynonym for sipe. F 870lateral for
