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BRITISH STANDARD AUTOMOBILE SERIES | | | | | | | | | | | | | | Passenger car tyres Ð Methods for measuring rolling circumference Ð Loaded new tyres | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | IC S 83 60 | | | | | | | | NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW | | | | | BS AU 50.1.1.2:2001 ISO 17269:2000 BS AU 50.1.1.2:2001 National foreword This British Standard reproduces verbatim ISO 17269:2000 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: Ð aid enquirers to understand the text; Ð present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; Ð monitor related international and European developments and promulgate them in the UK A list of organizations represented on this committee can be obtained on request to its secretary Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled ªInternational Standards Correspondence Indexº, or by using the ªFindº facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary 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 obligations Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages to 8, an inside back cover and a back cover The BSI copyright notice displayed in this document indicates when the document was last issued This British Standard, having been prepared under the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on April 2001 BSI 04-2001 ISBN 580 36849 Amendments issued since publication Amd No Date Comments INTERNATIONAL STANDARD BS AU 50.1.1.2:2001 I SO 7269 First edition 2000-1 2-01 Passen g er car tyres — M eth od s fo r m easu ri n g rol l i n g ci rcu m feren ce — Lo ad ed n ew tyres Pneumatiques pour voitures particulières — Méthodes de mesure de la circonférence de roulement — Pneumatiques neufs en charge Reference number ISO 7269:2000(E) BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E ii BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E Con ten ts Page Foreword i v Scope N orm ati ve referen ce Term s an d d efi n i ti on s Dru m m eth od Test m eth od u si n g veh i cl e An n exe A (informative) Test eq u i pm en t tol eran c es B i bl i og raph y iii BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E 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 International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 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 Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights ISO shall not be held responsible for identifying any or all such patent rights International Standard ISO 7269 was prepared by Technical Committee ISO/TC 31 , Subcommittee SC 3, Passenger car tyres and rims Annex A of this International Standard is for information only iv Tyres, rims and valves, BS AU 50.1.1.2:2001 I N TEN R ATI ON AL TSAN D ADR I SO 96271 : (0002 ) E Passen g er car tyres — M eth od s fo r m easu ri n g rol l i n g ci rcu m feren ce — Lo ad ed n ew tyres Scope This International Standard specifies two methods for measuring, under loaded conditions, the rolling circumference and revolutions per unit distance (kilometres) of new tyres for use on passenger cars The first is a drum method that consists of loading a test tyre mounted on a free axle against a driven road wheel, or drum, of specified diameter The second involves using a vehicle whose drive axle is equipped with the test tyres driven on a straight, paved road This International Standard is applicable to all passenger car tyres However, the values obtained from the measurements are not intended to be used as benchmarks for performance or quality N o rm ati ve referen ce The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard For dated references, subsequent amendments to, or revisions of, any of these publications not apply However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below For undated references, the latest edition of the normative document referred to applies Members of ISO and IEC maintain registers of currently valid International Standards ISO 4000-1 , Passenger car tyres and rims — Part 1: Tyres (metric series) Term s an d d efi n i ti o n s For the purposes of this International Standard, the following terms and definitions apply revo l u ti on s per u n i t d i st an ce number of tyre revolutions, and parts of revolutions, that occur when the (axle) centre of the tyre is moved a unit distance of exactly km; the number of tyre revolutions per kilometre is calculated as one divided by the tyre rolling circumference (in millimetres) multiplied by ro l l i n g ci rcu m feren ce of tyre Cr distance covered by the tyre during one complete revolution BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E Dru m m eth od Pri n ci pl e A test tyre mounted on a free axle is loaded against a driven road wheel (drum) of specified diameter The value of the rolling circumference is determined for a specified speed, the tyre and drum revolutions are counted and used in the formula, and the formula then used to determine the tyre’s rolling circumference 4 Test d ru m speci fi cati on s Di am eter The test drum shall have a diameter of at least ,20 m, with a free axle capable of holding and loading a tyre against the driven drum Care shall be taken to avoid galloping during measurements 2 Su rfac e The surface of the drum should preferably be of smooth steel In cases where a textured drum surface is used, this shall be noted in the test report The surface of the drum shall be kept clean Wi d th The width of the drum test surface shall exceed that of the test tyre tread Th erm al en vi ron m en t The test should preferably be carried out at a reference room temperature of 25 °C However, it may be performed in the range 20 °C to 30 °C No temperature correction is required 4 Speed In order to establish a basic reference for rolling circumference for all tyres, the drum velocity shall be 80 km/h For radial tyres, linear assumption is allowed for the relation between rolling circumference values and the speed of the tyre in the range 80 km/h ? 50 km/h, and the rolling circumference may be evaluated at 80 km/h by linear interpolation within that range Ac cu rac y The minimum number of impulses ( Ni ) per revolution of both the tyre and the drum shall be The total number of impulses during the time of measurement should be greater than 000 6 Test tyre param eters Lo ad The standard test loads shall be computed from 80 % of the load capacity, corresponding to the load index (LI) moulded on the tyre sidewall, or 80 % of the maximum permissible load Load application shall be kept normal to the test surface and shall pass within mrad of the wheel centre BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E Al i g n m en t Sl i p an g l e The plane of the tyre shall be parallel, within mrad, to the direction of the test surface motion 2 Cam ber an g l e The plane of the wheel shall be normal, within mrad, to the test surface I n fl ati on pressu re The inflation pressure of the test tyre at ambient temperature shall be 30 kPa less than the reference pressure for the tyre categories specified in annex B of ISO 4000-1 :2000 The pressure may be either regulated or capped For tyres not specified in ISO 4000-1 , the reference inflation pressure shall be that given by the tyre manufacturer Ri m s The rims used in the test should be of a size and type approved by the tyre manufacturer for use with the test tyres in highway service If such rims are not available, or the information is unknown, a standard measuring rim, or the rim nearest to it, shall be used in the test Proced u re a) To ensure repeatability of measurements, an initial break-in and cooling period can be necessary prior to the start of the test Carry out this break-in on a test drum of at least ,20 m, for a period of not less than one hour, at a minimum velocity of 80 km/h, and at the load and inflation pressure specified in 4.6.1 and 4.7 b) For future comparisons, record the overall diameter of the new tyre after the break-in c) Allow the tyre to stand, inflated, in the test area thermal environment in order for it to achieve thermal equilibrium, generally reached after h d) Adjust the inflation pressure to that specified in 4.7 and after about min, verify the load is as specified in 4.6.1 e) Rotate the drum at the test speed for approximately 30 to warm up the tyre After warm-up, the inflation pressure may not be readjusted under capped-pressure conditions, and the test shall be run with pressure build-up to simulate normal service conditions The values obtained under regulated pressure conditions will be similar to those obtained using capped pressure Cal cu l ati on Record the number of revolutions and parts of revolutions of the drum occurring during a time duration, T, taking care to ensure that, for both tyre and drum, the total number of impulses during T is greater than 000 1 Calculate the test tyre’s rolling circumference, Cr, in millimetres, using the formula: C r ? 2? ? Nd ? ? ? Nt ? ? R where Nd is the number of revolutions of the drum; Nt is the number of revolutions of the tyre; R is the radius of the drum, in millimetres BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E Results obtained with different drum diameters can be compared using the following empirical formula: C r, R 02 ? K ? C r, R 01 with K? ? ?R ? ? ? R ? ? R ? rT ? ? ? ?? ? R1 ? r T ? ?1 30 where R1 is the radius of drum , in millimetres; R2 is the radius of drum 2, in millimetres; rT is the nominal tyre radius, in millimetres; Cr, R01 is the rolling circumference measured on drum , in millimetres; Cr, R02 is the rolling circumference measured on drum 2, in millimetres Results obtained using the formula given in 4.1 0.2 can be correlated with those obtained by road simulation on a flat surface, which is carried out using the following empirical formula: 4 C rF ? K ? C rD with K? ? ? R1 ? R1 ? rT ? ? ? ?1 30 where R is the radius of drum , in millimetres; r T is the nominal tyre radius, in millimetres; CrD is the rolling circumference measured on the drum, in millimetres; CrF is the rolling circumference measured on a flat surface, in millimetres 5 Test m eth o d u si n g veh i cl e Pri n ci pl e This method consists of driving a typical vehicle whose drive axle is fitted with the test tyres at a constant speed on a straight, level, paved road, and counting the number of tyre revolutions, or parts of revolutions, that occur during the traversal of an accurately measured distance BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E 5 Con d i ti on s Cou rse The test course shall be a level, straight section of smooth, dry road, whose surface is of either asphalt or concrete pavement of medium roughness The maximum longitudinal and transverse gradient of the road shall be % The length of the course should preferably be 500 m, but may be longer depending on the accuracy of the test equipment (see 5.4) The length of the test course, expressed in metres, shall be measured to within 0,1 % There shall be an approach road at both ends of the test course to allow the course to be entered at the test speed 2 Weath er The ambient temperature shall be between °C and 30 °C However, any asphaltic surface shall be sufficiently cool so that the surface is not tacky The wind speed shall not exceed m/s Speed The test speed shall be in the range 80 km/h ? km/h For radial tyres, linear assumption is allowed for the relation between rolling circumference values and the speed of the tyre in the range 80 km/h ? 50 km/h Accu racy The minimum number of impulses per revolution shall be The overall error in the revolution-counting equipment, including start and stop errors, shall not exceed 0,1 % 5 Veh i cl e The test vehicle shall be representative of the size of vehicle normally fitted with tyres the same size as those being tested Because most speedometers and odometers are actuated from the drive-shaft, the test tyres shall be fitted to the drive axle For four-wheel drive vehicles, one or the other of the drive axles shall be disengaged during the test 6 Test tyre an d ri m param eters Tyres The tyres shall be a matched set of the same size, designation, type and brand, having inflated, unloaded overall diameters within 0,5 % of each other For future comparisons, record the overall diameter of the new tyres, measured according to ISO 4000-1 Lo ad The load on the drive axle shall be 80 % of the maximum rated tyre load multiplied by the number of tyres on the axle, to within ? % The tyres’ maximum load capacity corresponds to the LI moulded on the sidewall of the tyre If this is not marked, use the maximum permissible tyre load capacity BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E I n fl ati o n p res su re The inflation pressure of the test tyres at ambient temperature shall be 30 kPa less than the reference pressure for the tyre categories specified in annex B of ISO 4000-1 :2000 For tyres not specified in ISO 4000-1 , the reference inflation pressure shall be that given by the tyre manufacturer Ri m s The rims used in the test should be of a size and type approved by the tyre manufacturer for use with the test tyres in highway service If such rims are not available, or the information is unknown, a standard measuring rim, or the rim nearest to it, shall be used in the test Proced u re a) Prior to the test, break in and condition the tyres by running for at least half an hour at an average speed of approximately 80 km/h at the specified load and inflation pressure b) Immediately after conditioning, run the test at the speed and on the course specified c) Limit acceleration, braking, and steering to an absolute minimum during the measurements d) Record the number of revolutions, and parts of revolutions, of the right and left test wheels, during the time taken for the vehicle to complete the test course e) Repeat the test twice in both directions If the number of revolutions for each wheel on the second run differs from the first in the same direction by more than 0,2 %, repeat the test until two runs are obtained in each direction within this tolerance Cal cu l ati on Calculate for each of the eight readings (i.e four runs for each drive wheel) according to 4.3.9 e) and average the eight calculations to obtain the rated value To determine the rolling circumference, divide the test course length (in metres) by the number of revolutions measured and multiply this by Round this value to the nearest unit BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E An n ex A (informative) Test eq u i pm en t tol eran ces These limits are given in order to achieve suitable levels of repeatable test results that can be correlated among various test laboratories The tolerances are not intended to represent a complete set of engineering specifications for test equipment, but to serve as guidelines for achieving reliable test results Excluding perturbations induced by non-uniform tyres and rims, the test equipment should be capable of checking the test variables within the following limits: ? ? ? ? ? tyre loading: ? 50 N; inflation pressure: ? kPa; surface velocity: ? 0,5 km/h; drum measurement accuracy: ? mm; tyre angular velocity: ? 0,2 % BS AU 50.1.1.2:2001 I SO 96271 : (0002 ) E B i bl i og raph y [1 ] I SO 1 91 , [2 ] I S O 42 - , Passenger car tyres — Verifying tyre capabilities — Laboratory test methods Definitions ofsome terms used in the tyre industry — Part 1: Pneumatic tyres BS AU 50.1.1.2:2001 ISO 17269:2000 | | | | | | | | | BSI Ð British Standards Institution | | | | | | | BSI is the independent national body responsible for preparing British Standards It | | presents the UK view on standards in Europe and at the international level It is | | | | | incorporated by Royal Charter Revisions | | British Standards are updated by amendment or revision Users of British Standards | | should make sure that they possess the latest amendments or editions | | | It is the constant aim of BSI to improve the quality of our products and services We | | would be grateful if anyone finding an inaccuracy or ambiguity while using this | | | | | British Standard would inform the the identity of which can be Fax: 02 8996 Secretary of the found on the inside technical front cover committee Tel: 020 responsible, 8996 9000 7400 | | | BSI offers members an individual updating service called PLUS which ensures that | | | | | | subscribers automatically receive the latest editions of standards Buying standards | | | | | | Orders for all addressed to are also BSI, international and foreign standards Customer Services available from the BSI Tel: 02 8996 9001 website publications Fax: should be 02 8996 7001 Standards at http: //www bsi-global com | | In response to orders for international standards, it is BSI policy to supply the BSI | | implementation of those that have been published as British Standards, unless | | otherwise | Information on standards | | requested | | | | | | BSI provides a wide range standards through its BSI electronic of information on national, Library and its information services Technical Help are also European and international to available Exporters which give Service details Various on all its | | products and services Contact the Information Centre Tel: 020 8996 71 1 | | Fax: 02 8996 7048 | | | | | | | | Subscribing members of BSI receive these Fax: are substantial discounts and other benefits 02 8996 7001 kept up on the to date purchase contact Membership with standards price Administration Further information about BSI developments of standards is Tel: available For details 020 on the and of 8996 7002 BSI website | | | | | | at http: //www bsi-global com Copyright | | Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of | | | | | the publications of the under the Copyright, international standardization bodies Designs and Patents Act 988 no Except as extract may be permitted reproduced, stored in a retrieval system or transmitted in any form or by any means ± electronic, | | photocopying, recording or otherwise ± without prior written permission from BSI | | | This does not preclude the free use, in the course of implementing the standard, | | necessary details such as symbols, and size, type or grade designations If these | | | | details are to be used for any other purpose written permission of BSI must be than implementation then the prior obtained | | If permission is granted, the terms may include royalty payments or a licensing | | agreement Details | | | | | | | | BSI | 389 Chiswick High Road | | London | | W4 4AL | | | | | | | Tel: 02 8996 7070 and advice can be obtained from the Copyright Manager of