BRITISH STANDARD AUTOMOBILE SERIES BS AU 50-1 -6 7:1 998 ISO 327:1 998 Tyres and wheels Part : Tyres — Section 6: Motorcycle tyres — — Subsection 6.7 Method of test for measuring rolling resistance IC S 43 40; 83 60 óóÀơ ơ Àơ óÀ óÀơ Àơ ụ ụ ụ ụ úúú íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 0-1 -6.7:1 998 National foreword This British Standard reproduces verbatim ISO 3327: 998 and implements it as the UK national standard The UK participation in its preparation was entrusted to Technical Committee AUE/4, Tyres and wheels for motor vehicles, which has the responsibility to: — aid enquirers to understand the text; — present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; — monitor related international and European developments and óóÀô ô ô ô Àô óÀ óÀô ô Àô ô Àơ Àơ Àóóó promulgate them in the UK A list of organizations repres ented on this committee can be obtained on request to its secretary Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards “ “Find” facility of the BSI Standards Electronic Catalogue under the section entitled International Standards Corres pondence ” Index , or by using the Catalogue A British Standard does not purport to include all the necess ary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal ob ligations Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages to 8, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover This British Standard, having Amendments issued since publication been prepared under the direction of the E ngineering Sector Board, was published Amd No Date Comments under the authority of the Standards Board and comes into effect on November 998 © BSI 05- 999 ISBN 80 3061 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ λ-¿´» BS AU 0-1 -6.7:1 998 C ontents Page National foreword Inside front cover Foreword iii Text of IS O 33 27 óóÀơ ơ Àơ óÀ óÀơ Àơ Àơ Àơ Àóóó © i BS I 05 - 99 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ úúụ ụ ụ ô Àô óÀ óÀô ô Àô ô Àô Àô ô úúú ii ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà íĐđÃạáơ ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ blank ềơ đ ẻằ-ằ úúụ ụ ụ ụ ụ ú úụ ụ ụ ụ ụ ụ ụ úúú íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 50-1-6.7:1 998 C ontents Page Foreword iii Scope Normative reference Definitions Test methods Test equipment Test conditions Test procedure Data interpretation Data analysis Annex A (normative) Test equipment tolerances Annex B (informative) Measurement methods of moment of — Deceleration method Figure — Free- body diagram of tyre/drum s ystem, Inside back cover assuming no bearing and windage losses — Test arrangement — Spring method Figure B — Bifilar pendulum (rope) method Figure B.1 Figure B 8 © BSI 05- 999 ii íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ØÍ óóÀơ ơ Àơ óÀ óÀơ Àơ ô Àô Àô ô Àóóó inertia for drum and tyre as sembly Annex C (informative) Bibliography ềơ đ ẻằ-ằ BS AU 0-1 -6.7:1 998 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work of preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization Draft International Standards adopted by the technical committees are circulated to the member bodies for voting Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote International Standard ISO 13327 was prepared by Technical Committee ISO/TC 31, Subcommittee SC 10, Tyres , rim s and valves , Cy cle , m o ped, m oto rcy cle tyre s and rim s Annex A forms an integral part of this International Standard Annex B and Annex C are for information only óóÀơ ơ Àơ óÀ óÀơ Àơ ô Àô Àô ô Àóóó Descriptors: Road vehicles, motorcycles, tyres, pneumatic tyres, tests, laboratory tests, physical tests, rolling tests iii â BSI 05-1999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ úú ụ ụ ụ ụ ụ ó À ó À ô ô À ô ô À ụ ụ ụ ú ú ú ivịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà íĐđÃạáơ ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ blank ềơ đ ẻằ-ằ BS AU 0-1 -6.7:1 998 NOTE Scope This International Standard specifies methods for measuring rolling resistance, under controlled This quantity is dimensionless 3.3 capped inflation laboratory conditions, for new pneumatic tyres proces s of inflating the tyre and allowing the designed primarily for use on motorcycles The inflation pressure to build up, as the tyre is warmed relationship between values obtained and the fuel up while running economy of the vehicle is undetermined, and such 3.4 values are not intended to be used to indicate levels óóÀơ ơ Àơ óÀ óÀơ Àơ Àơ Àơ Àóóó of performance or quality This International Standard is applicable to all motorcycle tyres regulated inflation process of inflating the tyre to the required pressure independent of its temperature, and maintaining this inflation press ure while the tyre runs under It enables comparisons to be made between the load rolling resistance of new tyres when they are NOTE free- rolling s traight ahead, in a position pressure source attached to the tyre through a rotating union perpendicular to the drum outer surface, and in steady- state conditions This is most commonly done by using a regulated 3.5 parasitic loss In measuring tyre rolling resistance, it is necessary to measure small forces in the presence of much larger forces It is, therefore, essential that loss of energy (or energy consumed) per unit distance excluding tyre losses, and attributable to aerodynamic loss, bearing friction and other s ources equipment and instrumentation of app ropriate of systematic loss which may be inherent in the accuracy be used measurement 3.6 Normative reference The following standard contains p rovisions which, through reference in this text, constitute p rovisions of this International Standard At the time of publication, the edition indicated was valid All standards are subj ect to revision and parties to skim reading type of parasitic loss meas urement, in which the tyre is kept rolling, without slippage, while reducing the tyre load to a level at which energy loss within the tyre itself is virtually zero agreements bas ed on this International Standard 3.7 are encouraged to investigate the poss ibility of machine reading app lying the most recent edition of the standard indicated below Members of IEC and ISO maintain registers of currently valid International Standards — ISO 4223- : 1989, the tyre industry type of parasitic loss measurement, involving losses of the test machine, exclusive of losses in the rotating spindle which carries the tyre and rim De finitions o f so me term s us ed in Test methods Part : Pneum atic ty re s The following alternative measurement methods Definitions are given in this International Standard: For the purposes of this International Standard, the definitions given in ISO 4223- and the following definitions apply a) Force method: the reaction force at the tyre spindle b) Torque method: the torque input to the test 3.1 drum rolling resistance c) Power method: the power input to the test drum F r loss of energy (or energy consumed) per unit of d) D eceleration method: the deceleration of the distance test drum and tyre assembly NOTE The SI unit conventionally used for the rolling resistance · is the newton metre per metre (N m/m) this is equivalent to the drag force in newtons (N) 3.2 rolling resistance coefficient C r ratio of the rolling resistance, in newtons, to the load on the tyre, in newtons © BSI 05 -1 999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU -1 -6 7: 998 50 km/h for tyres marked with a speed symbol Test equip ment “L” and below D rum s pe ci fi cati ons 5.1 Diameter Te st load The test dynamometer shall have a cylindrical flywheel (drum) with a diameter of between 1,5 m and m inclusive (reference drum diameter: 1,70 m) It should be noted that the results are different; see for drum diameter correction for comparisons, if necessary 5.1 Surface The surface of the drum shall be smooth steel or textured and shall be kept clean (see clause ) The standard test load shall be computed from 65 % of the maximum load capacity of the tyre for light and standard load versions; 80 % of the maximum load capacity of the tyre for reinforced version It shall be kept within the tolerance specified in Annex A Te st inflati on pres sure The inflation pressure shall be 200 kPa for light and standard load versions; The width of the drum test surface shall exceed the 250 kPa for reinforced version width of the test tyre tread The inflation pressure shall be capped with the accuracy specified in The tyre shall be mounted on a test rim, as specified in Annex A When the deceleration method is selected, the following requirements apply: a) for duration, ût, the time increments shall not exceed 0,5 s; Measurement of these parameters shall be sufficiently accurate and precise to provide the b) any variation of the test drum velocity shall not required test data The specific and respective exceed km/h values are shown in Annex A A 5.1 Width A Te st rim D urati on and velocity Load, ali gnment, control and i ns trume ntation accuracy The rmal environme nt 5.4.1 Reference conditions Tes t procedure Ge neral The choice of an individual method is left to the tester For each method, the test measurements shall be converted to a rolling resistance force acting at the tyre/drum interface The test procedure steps described in to shall Alternative conditions be followed in the sequence given If the reference temperature cannot be obtained, the rolling resistance measurement shall be corrected to standard temperature conditions in accordance To ensure repeatability of measurements, an initial with break-in and cooling period is required prior to the start of the test Such a break-in should be carried Drum surface temperature out on a test drum of at least 1,5 m diameter for a Care should be taken to ensure that the period of at least h, at a minimum velocity temperature of the test drum surface is of 80 km/h, with the load and inflation pressure approximately the same as the ambient given in and respectively temperature at the beginning of the test The reference ambient temperature, as measured on the rotational axis of the tyre, m away from the plane touching the nearest tyre sidewall, shall be 25 °C 5.4.2 7 Bre ak-i n 5.4.3 óóÀơ ơ ô Àô óÀ óÀô ô Àô ô Àô Àô ô Àóóó Test cond iti ons The test consists of a measurement of rolling resistance in which the tyre is inflated and the inflation pressure allowed to build up (i.e “capped air” ) Te st s pe eds The value shall be obtained at a drum velocity of 80 km/h for tyres marked with a speed symbol above “L”; The rmal conditi oni ng Place the inflated tyre in the thermal environment of the test location for at least h P re ss ure adj us tme nt After thermal conditioning, the inflation pressure shall be adjusted to the test pressure, and verified 10 after the adjustment was made © BSI 05-1999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU -1 -6 7: 998 Fi gure — Fre e-bod y diagram of tyre/drum s ystem, as suming no be ari ng and wi ndage los se s Warm-up h) test method chosen; The tyre s hall be run at constant test velocity until i) test rim (designation and material) reaching a stabilised steady- state value of rolling resis tance A warm- up period of at least 30 at the test speed is required 7 Me asure ment of paras iti c los s es Determine parasitic loss es by one of the procedures given in Me asurement and re cordi ng 7 The following shall be measured and recorded (see Figure ): a) test velocity, 7 Skim reading a) Reduce the load to maintain the tyre at the test U n; m; ) initial, as defined in b) Record the spindle force, F , input torque, T , p surface, , NOTE T , the F , the input p ower, V I A, or d) the driving torque on the drive shaft, L p The measured value includes the bearing and aerodynamic losses of the wheel, the tyre, and the drum losses 2) final, for capped inflation; t t Machine reading which are also to b e considered 7 the deceleration of the test drum/tyre/wheel a) Remove the tyre from the drum s urface assembly, b) At the test velocity, ûV/ût, depending on the method; e) distance, r (see ); ; f) ambient temperature, t g) test drum radius, R; L p or the power, whichever applies c) Record the load on the tyre normal to the drum c) test inflation pressure: tyre spindle force, to velocity without slippage to, for example, 50 N b) load on the tyre normal to the drum surface, L 7 torque, U , record the input T , the power, or the test drum n p deceleration, whichever app lies amb NOTE The measured value includes the drum losses to be considered óóÀơ ơ Àơ óÀ óÀơ Àơ Àơ Àơ Àóóó © BSI 05 -1 999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 50-1-6.7:1 998 7.7.3 Deceleration method Force method at tyre spindle 8.2 a) Remove the tyre from the test surface The rolling resistance, b) Record the deceleration of the test with the equation: ûV /ût and that of the unloaded ûV /ût drum, tyre, NOTE F o po = r F r L outer surface under steady- state conditions, in Data interpretation metres; R is the test drum radius , in metres 8.1 Subtraction of parasitic losses The parasitic losses shall be subtracted as shown in 8.1 , 8.1 or 8.1 Skim reading Torque method at drum axis 8.2 The rolling resistance, F , in newtons, is calculated r with the equation Subtract the skim reading from the test measurement F r Machine reading T R = where T is the input torque, in newton metres; R is the test drum radius , in metres Subtract the machine reading from the test measurement When the machine reading method is used to determine parasitic losses for the torque or power method, the resulting rolling resistance includes aerodynamic losses of the tyre and wheel as well as the tyre-spindle friction Parasitic losses for the deceleration method 8.1 Calculate the paras itic losses t is the distance from the tyre axis to the drum L NOTE F [1 + (r /R)] is the tyre spindle force, in newtons; t aerodynamic losses of the wheel, the tyre, and the drum losses 8.1 r where The measured value includes the bearing and which are also to b e considered 8.1 F , in newtons, is calculated F Power method at drum axis 8.2 The rolling resistance, F , in newtons, is calculated r with the equation F r V A U 3, = × n pl , in newtons as where V is the electrical potential applied to the machine drive, in volts; A is the electric current drawn by the machine I is the tes t drum inertia in rotation, in D kilogram metres squared; R is the test drum surface radius, in metres; V is the test drum angular velocity, without vo tyre, in radians per second; ût o is the time increment chos en for the drive, in amperes; U is the test drum velocity, in kilometres per n hour 8.2 Deceleration method The rolling resistance, F , in newtons, is calculated r with the equation measurement of the parasitic losses without tyre, in seconds; I T is the tyre and wheel inertia in rotation, in kilogram metres squared; R V r is the tyre rolling radius , in metres; po is the tyre angular velocity, unloaded tyre, in radians per second 8.2 Rolling resistance calculation The net values of driving torque, spindle force, where I is the test drum inertia in rotation, in D kilogram metres squared; R is the test drum surface radius , in metres; ût is the time increment chosen for v measurement, in s econds; power or deceleration are to be converted to rolling V resistance, in radians per second; F , expressed in newtons, using the r appropriate method, as shown in 8.2 to 8.2 I v T is the test drum angular velocity, loaded tyre, is the tyre and wheel inertia in rotation, in kilogram metres squared; ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà íĐđÃạáơ ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ â BSI 05- 19 99 ềơ đ Ỵ»-¿´» óó À ơ ơ À ó À ó À ơ À ơ À À ơ À ó ó ó where BS AU 0-1 -6.7:1 998 R F is the tyre rolling radius, in metres; r 9.3 D rum d iameter correction Test results obtained from different drum diameters is as defined in 8.1 pl Annex B gives guidelines and practical examples to measure the moments of inertia for the deceleration method may be compared by using the following theoretical formula: F ú KF r02 r01 with D ata analysis 9.1 Rolling re sistance coefficient The rolling resistance coefficient, C , is calculated r by dividing the rolling resistance by the load on the tyre: C r m T where F L r is the radius of drum , in metres; is the radius of drum 2, in metres; is the nominal tyre radius, in metres; r01 is the rolling resistance, in newtons ; m R R r F F L = r where is the rolling resistance value measured on drum , in newtons; F is the test load, in newtons r02 9.2 Temp erature correction If measurements at temperatures other than 25 °C is the rolling resistance value measured on drum 2, in newtons are unavoidable (only temperatures not less than 20 °C nor more than 30 °C are acceptable), then a correction for temperature shall be made F is the ° C, in newtons: using the following equation, where rolling resistance referred at 25 F r25 = F [1 + K(t r amb – 25)] r25 where F t r is the rolling resistance, in newtons ; amb is the ambient temperature, in degrees Celsius; óóÀơ ơ Àơ óÀ óÀô ô Àô ô Àô Àô ô Àóóó K is equal to 0, 01 for motorcycle tyres © BSI 05 -1 999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 50-1-6.7:1 998 úúụ ụ ụ ụ Àơ óÀ óÀơ Àơ Àơ Àơ Àóóó Annex A (normative) Test equipment tolerances A.1 Purpose The limits specified in this annex are necessary in order to achieve suitable levels of repeatable test results, which can also be correlated among various test laboratories These tolerances are not meant to represent a complete set of engineering specifications for test equipment; instead, they should serve as guidelines for achieving reliable test results — time: o 0,02 s; — angular velocity: o 0,2 % A.4.2 Optional comp ensation for load/sp indle force interaction and load misalignment Compensation of both load/spindle force interaction (“cross talk” ) and load misalignment may be accomplished either by recording the spindle force for both forward and reverse tyre rotation or by dynamic machine calibration If spindle force is recorded for forward and reverse directions (at each test condition), compensation is achieved by subtracting the “reverse” value from the “forward” A.2 Test rims value and dividing the result by two If dynamic A.2.1 Width machine calibration is intended, the compensation The test rim width shall be equal to the terms may be easily incorporated in the data standardized measuring rim If this is not available, reduction then the next wider rim may be chosen It should be NOTE This compensation applies for the force method only noted that a change in rim width will result in A.5 Instrumentation accuracy different test results The instrumentation used for readout and recording A.2.2 Run-out of test data shall be accurate within the tolerances Run-out shall meet the following criteria: stated below: — maximum radial run-out: 0,5 mm; — tyre load: o 10 N; — maximum lateral run-out: 0,5 mm — inflation pressure: o kPa; A.3 Alignment — spindle force: o 0,5 N; Angle deviations are critical to the test results — torque input: o 0,5 N·m; A.3.1 Load ap plic ation — distance: o mm; The direction of tyre loading application shall be — electrical power: o 10 W; kept normal to the test surface and shall pass — temperature: o 0,2 °C; through the wheel centre within — surface velocity: o 0,1 km/h (for all methods); mrad for the force and deceleration methods; — time: o 0,01 s; mrad for the torque and power methods — angular velocity: o 0,1% A.3.2 Tyre a lignment A.6 Test surface roughness A.3.2.1 Camber angle The roughness, measured laterally, of the smooth The plane of the wheel shall be normal to the test steel drum surface shall have a maximum surface within mrad for all methods centreline average height value of 6,3 ìm A.3.2.2 Slip angle In cases where a textured drum surface is used The plane of the tyre shall be parallel to the instead of a smooth steel surface, this fact shall be direction of the test surface motion within mrad noted in the test report The surface texture shall for all methods then be 180 ìm deep (80 grit) A.4 Control accuracy A.4.1 General accuracy Exclusive of perturbations induced by the tyre and rim non-uniformity, the test equipment shall be capable of checking the test variables within the following limits: — tyre loading: o 20 N; — inflation pressure: o kPa; — surface velocity: o 0,2 km/h for the power, torque and deceleration methods, o 0,5 km/h for the force method; A.7 Tyre spindle bearing friction When using the machine reading as a method for determining the parasitic losses, tyre spindle bearing friction should be regularly verified as being sufficiently small as to be considered negligible (e.g a coast-down from 80 km/h to km/h in not less than with a freely rotating tyre) â BSI 05-1999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 50-1 -6.7:1 998 Annex B (informative) I p — Measurement methods of moment of inertia for drum and tyre assembly Deceleration method is the pulley inertia, in kilogram metres squared; B.1 Limitation r is the pulley radius, in metres; R is the drum radius, in metres; I is the drum inertia, in kilogram metres The methods presented here s hould be considered squared; D only as guidelines or practical examples of methods used to measure moments of inertia by the newton metres; deceleration method to achieve reliable test results B.2 Test drum inertia B.2.1 Measurement method B.2.1.1 C is the friction torque of drum bearings, in g is the earth’s gravity equal to 9, 81 m/s ûV /ût is the angular acceleration or ; D deceleration, in radians per second squared Equipment needed NOTE óóÀơ ơ Àơ óÀ óÀơ ô Àô ô Àô Àô ô Àóóó The arrangement shown in Figure B requires , in addition to the drum and its angular encoder: — a lightweight pulley mounted on low- friction bearings; — a weight of known mass, m , in the range 50 kg to 100 kg; The friction torque of pulley b earings can be neglected B.2.1.4 Method When the mass, m , is released, the angular acceleration is measured through the angular encoder fitted to the drum axle (and otherwise used to measure drum decelerations) C, of drum bearings can also be The friction torque, — suitable wire rope and attachments B.2.1.2 Experimental arrangement measured, provided that the rope can be separated from the drum once mass, m , has given sufficient momentum to the drum, for the subsequent drum See Figure B deceleration is directly related to C by: where the values are as defined B.2.1 B.2.1.5 Determination method The drum inertia is estimated by calculation The drum inertia, I D, in kilogram metre squared, is determined by the summation of the inertia of each drum p art (flange, disc, reinforced rib): I D = I +I f d + I r where I is the drum flange inertia; I is the drum disc inertia; I is the reinforced rib inertia; f d r all values being express ed in kilogram metres Figure B.1 B.2.1.3 Theory — squared B.3 Tyre assembly inertia Test arrangement B.3.1 Spring method B.3.1.1 Application of laws of mechanics to the system shown in Figure B leads to the following equation: Equipment needed Torsion pendulum of inertia K (see Figure B 2) I o and spring constant where m is the mass , in kilograms; â BSI 05 -1 999 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ ềơ đ ẻằ-ằ BS AU 50-1-6.7:1 998 Figure B.2 B.3.1.2 — Spring method Theory Equation of free movement of pendulum, if F is the angle from equilibrium: Figure B.3 — Bifilar pendulum (rope) method B.3 2.1 To : Natural oscillation period, Theory IT, The tyre inertia, in kilogram metres squared, is determined by where F is the angle of oscillation, in radians; t is the period of time, in seconds; Io is the torsion pendulum inertia, in kilogram metres s quared; K is B.3.1.3 the spring cons tant b Measurement of oscillation periods, with the tyre assembly, T1 , G is the oscillation period, in seconds; W is the tyre and wheel weight, in newtons; a is the distance between points A and B, in metres; Method T0 , IT, and without, the tyre assembly inertia, where can be used to give is the distance between points C and D, in metres; h is the vertical distance between lines AB and CD , in metres B.3.2.2 B.3.2 Bifilar pendulum (rope) method Tyre inertia can be obtained by the p eriod time of Method The time period, G, of the twisted oscillation of a tyre is measured, and tyre inertia can be calculated from the equation given in B.3.2.1 twisted oscillation of a tyre hanging from two steel ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà íĐđÃạáơ ẻằđẳôẵằẳ ắĐ ì ỉ ôẳằđ Ãẵằ-ằ âÃơá ịì ú ậ ẵơđằẳ íĐ ề đằđẳôẵơà đ ằơâđàÃạ ằđÃơơằẳ âÃơáôơ Ãẵằ-ằ đ ì ỉ â BSI 05- 19 99 ềơ đ ẻằ-ằ úú ụ ụ ô ô À ô ó À ó À ô ô À ơ À À ơ À ó ó ó ropes of exactly the same length (see Figure B 3) BS AU 50-1 -6.7:1 998 Annex C (informative) Bibliography — Part : Tyres Motorcycles tyres and rims (code designated series) — Part 2: Tyre load ratings Motorcycles tyres and rims (code designated series) — Part 3: Rims Motorcycle tyres and rims (metric series) — Part : Design guides Motorcycle tyres and rims (metric series) — Part 2: Dimensions and load-carrying capacities Motorcycle tyres and rims (metric series) — Part 3: Range of approved rim contours Moped tyres and rims — Part : Tyres Moped tyres and rims — Part 2: Rims Motorcycle tyres and rims (code-designated series) — Diameter codes to — Part : Tyres Motorcycle tyres and rims (code-designated series) — Diameter codes to — Part 2: Rims [1 ] ISO 42 49 - : 5, Motorcycles tyres and rims (code designated series) [2 ] ISO 42 49 - 2: 9 0, [3 ] ISO 42 49 - 3: 9 7, [4 ] ISO 57 - : 9 4, [5 ] ISO 57 - 2: 9 4, [6 ] ISO 57 - 3: 9 4, [8 ] ISO 59 - 2: 8, [9 ] ISO 60 - : 9 4, [1 ] IS O 60 4- 2: 9 0, © BS I 05 - 99 íĐđÃạáơ ịđÃơÃ-á ơẳđẳ- ì-ơÃơôơà ẻằđẳôẵằẳ ắĐ ì ỉ 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