1、BSI Standards PublicationBS ISO 23671:2015Passenger car tyres Methodfor measuring relative wet gripperformance Loaded newtyresBS ISO 23671:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 23671:2015. It supersedes BS ISO 23671:2006 which is withdrawn.The UK
2、 participation in its preparation was entrusted to Technical Committee AUE/4, Tyres and wheels for motor vehicles.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract.
3、 Users are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015ISBN 978 0 580 85360 9 ICS 83.160.10 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the autho
4、rity of the Standards Policy and Strategy Committee on 30 September 2015.Amendments/corrigenda issued since publicationDate Text affectedBS ISO 23671:2015 ISO 2015Passenger car tyres Method for measuring relative wet grip performance Loaded new tyresPneumatiques pour voitures particulires Mthode de
5、mesure de ladhrence relative sur revtement mouill Pneumatiques neufs en chargeINTERNATIONAL STANDARDISO23671Second edition2015-09-01Reference numberISO 23671:2015(E)BS ISO 23671:2015ISO 23671:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rig
6、hts reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from e
7、ither ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 23671:2015ISO 23671:2015(E)Foreword iv1 Scope . 12 Normative
8、 references 13 Terms and definitions . 14 Methods for measuring wet grip 25 General test conditions 25.1 Track characteristics 25.2 Wetting conditions . 35.3 Atmospheric conditions 45.4 Reference tyre 46 Measurement of tyre wet grip on a standard vehicle . 46.1 Principle 46.2 Equipment . 46.2.1 Vehi
9、cle . 46.2.2 Measuring equipment .46.3 Conditioning of the test track . 56.4 Test speed measurement requirements 56.5 Tyres and rims . 56.5.1 Tyre preparation and break-in 56.5.2 Tyre load . 56.5.3 Tyre inflation pressure . 56.6 Procedure 56.7 Processing of measurement results 66.7.1 Calculation of
10、the average deceleration, AD .66.7.2 Validation of results 66.7.3 Calculation of average, AD .76.7.4 Calculation of braking force coefficient, BFC .76.7.5 Calculation of the relative wet grip performance index of the tyre . 76.8 Wet grip performance comparison between a candidate tyre and a referenc
11、e tyre using a control tyre . 86.8.1 General 86.8.2 Principle of the approach . 86.8.3 Selection of a control tyre set . 96.8.4 Storage and preservation . 96.8.5 Replacement of control tyres 97 Test method using a trailer or a tyre test vehicle . 97.1 Principle 97.2 Test apparatus . 97.3 Selection a
12、nd preparation of test tyres . 117.4 Preparation of apparatus and test track 117.4.1 Towed trailer 117.4.2 Tyre test vehicle.127.4.3 Instrumentation and equipment. 127.4.4 Conditioning of the track . 127.5 General test conditions . 127.6 Procedure . 127.7 Processing of measurement results . 13Annex
13、A (informative) Example test report of wet grip index 15Bibliography .18 ISO 2015 All rights reserved iiiContents PageBS ISO 23671:2015ISO 23671:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wor
14、k 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-governme
15、ntal, 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.The procedures used to develop this document and those intended for its further maintenance are described in the
16、 ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possib
17、ility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of
18、patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as in
19、formation about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 31, Tyres, rims and valves, Subcommittee SC 3, Passenger car tyres and rims.This second editi
20、on cancels and replaces the first edition (ISO 23671:2006), which has been technically revised.iv ISO 2015 All rights reservedBS ISO 23671:2015INTERNATIONAL STANDARD ISO 23671:2015(E)Passenger car tyres Method for measuring relative wet grip performance Loaded new tyres1 ScopeThis International Stan
21、dard specifies the method for measuring relative wet grip braking performance index to a reference under loaded conditions for new tyres for use on passenger cars on a wet-paved surface.The methods developed are meant to reduce variability. The use of a reference tyre is necessary to limit the varia
22、bility of the testing procedures.This International Standard applies to all passenger car tyres.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited appl
23、ies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 4000-1, Passenger car tyres and rims Part 1: Tyres (metric series)ASTM E303-93 (Reapproved 2013), Standard Test Method for Measuring Surface Frictional Properties Using the British Pendu
24、lum TesterASTM E501-08, Standard Specification for Standard Rib Tire for Pavement Skid-Resistance TestsASTM E965-96 (Reapproved 2006), Standard Test Method for Measuring Pavement Macro texture Depth Using a Volumetric TechniqueASTM E1136-93 (Reapproved 2003), Standard Specification for A Radial Stan
25、dard Reference Test TireASTM F2493-08, Standard Specification for P225/60R16 97S Radial Standard Reference Test TireEN 13036-1, Road and airfield surface characteristics Test methods Part 1: Measurement of pavement surface macrotexture depth using a volumetric patch technique3 Terms and definitionsF
26、or the purposes of this document, the following terms and definitions apply.3.1test runsingle pass of a loaded tyre over a given test surface3.2candidate tyre test tyre (set) that is part of an evaluation programme3.3reference tyrespecial test tyre (set) that is used as a benchmark in an evaluation
27、programme Note 1 to entry: These tyres usually have carefully controlled design features to minimize variation.Note 2 to entry: See ASTM F2493-08 P225/60R16. ISO 2015 All rights reserved 1BS ISO 23671:2015ISO 23671:2015(E)3.4control tyretyre (set) that is part of an evaluation programme; it is an in
28、termediate tyre (set) which is used when the candidate tyre and the reference tyre cannot be directly compared on the same vehicle3.5braking force of a tyrelongitudinal force, expressed in newtons, resulting from braking torque application3.6braking force coefficient of a tyreratio of braking force
29、to vertical load3.7peak braking force coefficient of a tyremaximum value of tyre braking force coefficient that occurs prior to wheel lockup as the braking torque is progressively increased3.8lockup of a wheelcondition of a wheel in which its rotational velocity about the wheel spin axis is zero and
30、 it is prevented from rotating in the presence of applied wheel torque3.9vertical loadnormal reaction of the tyre on the road3.10tyre test vehiclededicated vehicle which has instruments to measure the vertical and the longitudinal forces on one tyre during braking4 Methods for measuring wet gripRela
31、tive wet grip braking performance for loaded passenger car new tyres travelling straight ahead on a wet, paved surface can be measured by one of the following methods: vehicle method consisting of testing a set of tyres mounted on a standard vehicle; test method using a trailer or a tyre test vehicl
32、e equipped with the test tyres.5 General test conditions5.1 Track characteristicsThe surface shall have a uniform grade of not more than 2 % and shall not deviate more than 6 mm when tested with a 3 m straight edge.The test surface shall have a pavement of uniform age, composition, and wear. The tes
33、t surface shall be free of loose material and foreign deposits.It shall be a dense asphalt surface.The maximum chipping size shall be from 8 mm to 13 mm.The texture depth measured as specified in EN 13036-1 and ASTM E965-96 (Reapproved 2006) shall be (0,7 0,3) mm.In order to verify the frictional pr
34、operties of the surface, a) or b) shall be used.2 ISO 2015 All rights reservedBS ISO 23671:2015ISO 23671:2015(E)a) British Pendulum Number (BPN) methodThe averaged British Pendulum Number (BPN) British Pendulum Tester method as specified in ASTM E303-93 (Reapproved 2013) using the pad as specified i
35、n ASTM E501-08 shall be between 42 BPN and 60 BPN after temperature correction.Pad rubber component formulation and physical properties are to be requested.BPN shall be corrected by the wetted road surface temperature. Unless temperature correction recommendations are indicated by the British pendul
36、um manufacturer, the following formulae can be used:Temperature correction = 0,001 8 t2+ 0,34 t 6,1 (1)BPN = BPN (measured value) + temperature correction (2)where t is the wetted road surface temperature, in degrees Celsius.Effects of slider pad wear: The pad shall be removed for maximum wear when
37、the wear on the striking edge of the slider reaches 3,2 mm in the plane of the slider or 1,6 mm vertical to it in accordance with ASTM E303-93 (Reapproved 2013), 5.2.2 and Figure 3.Checking track surface BPN constancy for the measurement of wet grip on a standard vehicle: To decrease the dispersion
38、of test results, the BPN values of the track should not vary over the entire stopping distance. The operation shall be repeated five times at each point of the BPN measurement. The BPN shall be measured every 10 m on the braking lane and the coefficient of variation of the BPN averages shall not exc
39、eed 10 %.b) ASTM E1136-93 (Reapproved 2003) Standard Reference Test Tyre methodThe average peak braking force coefficient (peak,ave) of the ASTM E1136-93 (Reapproved 2003) (see Clause 7) shall be 0,7 0,1 at 65 km/h.For the trailer method, testing is run in such a way that braking occurs within 2 m o
40、f where the surface was examined.The average peak braking force coefficient (peak,ave) of the ASTM E1136-93 (Reapproved 2003) shall be corrected by the wetted road surface temperature:temperature correction = 0,0035 (t 20) (3)peak braking force coefficient (peak,ave) = peak braking force coefficient
41、 (measured) + temperature correction (4)where t is the wetted road surface temperature, in degrees Celsius.5.2 Wetting conditionsThe surface can be wetted from the track-side or by a wetting system incorporated in the test vehicle or the trailer.If “external watering” is used, water the test surface
42、 at least half an hour prior to testing in order to equalize the surface temperature and water temperature. External watering should be supplied continuously throughout testing.For the whole testing area, the water depth shall be between 0,5 mm and 1,5 mm. ISO 2015 All rights reserved 3BS ISO 23671:
43、2015ISO 23671:2015(E)5.3 Atmospheric conditionsThe wind conditions shall not interfere with wetting of the surface (wind-shields are allowed).Both the wetted surface and the ambient temperature shall be between 2 C and 20 C for the snow tyres, and 5C and 35 C for the normal tyres.Moreover, the wette
44、d surface temperature shall not vary during the test by more than 10 C.The ambient temperature must remain close to the wetted surface temperature; the difference between the ambient and the wetted surface temperature must be less than 10 C.5.4 Reference tyreThe specifications of the SRTT, tyre size
45、 P225/60R16, are defined in ASTM F2493-08.6 Measurement of tyre wet grip on a standard vehicle6.1 PrincipleThe test method covers a procedure for measuring the deceleration performance of passenger car tyres during braking, using an instrumented passenger car having an Antilock Braking System (ABS).
46、Starting with a defined initial speed, the brakes are applied hard enough on four wheels at the same time to activate the ABS. The average deceleration is calculated between two defined speeds, with an initial speed of 80 km/h and a final speed of 20 km/h.6.2 Equipment6.2.1 VehiclePermitted modifica
47、tions using a standard-model passenger car equipped with an ABS are as follows: those allowing the number of tyre sizes that can be mounted on the vehicle to be increased; those permitting automatic activation of the braking device to be installed.Any other modification of the braking system is proh
48、ibited.6.2.2 Measuring equipmentThe exposed portions of the system shall tolerate 100 % relative humidity (rain or spray) and all other conditions, such as dust, shock and vibrations, which can be encountered in regular operation.The vehicle shall be fitted with a sensor suitable for measuring speed
49、 on a wet surface and distance covered between two speeds.To measure vehicle speed, a fifth wheel or non-contact precision (including radar, GPS, etc.) speed-measuring system shall be used.The following tolerances shall be respected: for speed measurement: 1 % or 0,5 km/h, whichever is greater; for distance: 1 101m.4 ISO 2015 All rights reservedBS ISO 23671:2015ISO 23671:2015(E)The measured speed or the difference between the measured speed and the reference speed for the test should be displayed i
