ISO-9112-2008.pdf

INTERNATIONAL STANDARD ISO 9112 Second edition 2008-02-15 Reference number ISO 9112:2008(E) © ISO 2008 Truck and bus tyres Methods of measuring tyre rolling circumference Loaded new tyres Pneumatiques pour véhicules utilitaires et autobus Méthodes de mesure de la circonférence de roulement Pneumatiques neufs en charge Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) ii© ISO 2008 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT © ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) © ISO 2008 All rights reserved iii 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 2. The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 9112 was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves, Subcommittee SC 4, Truck and bus tyres and rims. This second edition cancels and replaces the first edition (ISO 9112:1991), which has been technically revised. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) iv© ISO 2008 All rights reserved Introduction The distance covered by a vehicle in a straight line in one wheel revolution is information that is increasingly used by the electronic systems in vehicles. One reason is that it makes it possible to indicate the instantaneous vehicle speed to the driver. Its evaluation uses the rolling circumference of the tyre in normal usage conditions: tyre deflected by the carried load and inflated to an adapted pressure level. A standardized measuring method is necessary because some parameters, such as tyre load and pressure, can cause the rolling circumference to change. This International Standard contributes to tyres being interchangeable for a given vehicle. Its application by tyre manufacturers allows confidence to be maintained in the information provided to the driver, especially concerning speed and distance travelled. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARDISO 9112:2008(E) © ISO 2008 All rights reserved 1 Truck and bus tyres Methods of measuring tyre rolling circumference Loaded new tyres 1Scope This International Standard specifies two methods for measuring the rolling circumference and the number of revolutions per unit distance (kilometre) of new commercial vehicle tyres, under loaded conditions, for use on trucks and buses. The first method is a drum method consisting of loading a test tyre mounted on a free axle against a driven road wheel (or drum) of specified diameter. The second method involves a vehicle whose drive axle is equipped with the test tyres driven on a straight, paved road. The values thus obtained are not intended for use as levels of performance or quality. This International Standard applies to all truck and bus tyres. NOTEThis International Standard applies not only to large truck and bus tyres, but also to small truck and bus tyres, which are called “light truck tyres” in some countries. 2Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4209-1, Truck and bus tyres and rims (metric series) Part 1: Tyres 3Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 revolutions per unit distance number of tyre revolutions (and portions thereof) that occur when the (axle) centre of the tyre is moved exactly the unit distance of , under the conditions specified in this International Standard 3.2 rolling circumference of tyre distance that the (axle) centre of the tyre moves in one revolution of the tyre, under the conditions specified in this International Standard 3.3 reference speed speed at which the test is intended to be performed and which is related to the delivered value of the rolling circumference 1 km Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) 2© ISO 2008 All rights reserved 4Drum method 4.1Principle 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 to determine the tyre's rolling circumference. 4.2Test drum specifications 4.2.1Diameter The test drum shall have a diameter of at least , with a free axle capable of holding and loading a tyre against the driven drum. Care shall be taken to avoid low frequency bouncing. 4.2.2Surface 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. 4.2.3Width The width of the drum surface shall exceed that of the test tyre tread. 4.3Thermal environment The test should preferably be carried out at a reference room temperature of . However, it may be performed in the range to . No temperature correction is required. 4.4Test speed 4.4.1Test speed for load index 122 and above In order to establish a basic reference for rolling circumference for all tyres, the rolling circumference shall be given for a drum speed of for tyres with speed symbols K to M inclusive, and for a drum speed of for tyres with speed symbols F to J. For tyres that bear the mandatory marking “max. speed ” or “max. speed ”, and for tyres not marked with a speed symbol, the drum speed shall be . For radial tyres, the measurements can be performed within the speed interval from to , and the end result may be calculated by linear interpolation. 4.4.2Test speed for load index 121 and below In order to establish a basic reference for rolling circumference for all tyres, the rolling circumference shall be given for a drum speed of . NOTEThis also applies to tyres without speed symbol on the sidewall. For radial tyres, the measurements can be performed within the speed interval from to , and the end result may be calculated by linear interpolation. 1,7 m 25 C 20 C 30 C 80 km/h 60 km/h 55 mph/88 km/h50 mph/80 km/h 60 km/h 30 km/h130 km/h 80 km/h 30 km/h130 km/h Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) © ISO 2008 All rights reserved 3 4.5Accuracy The minimum number of impulses () per revolution of both the tyre and the drum shall be 10. The total number of impulses during the time of measurement should be greater than 1 000. 4.6Test tyre parameters 4.6.1Load The standard test load shall be of the maximum single load capacity of the tyre. 4.6.2Alignment The specific values are shown in Annex A. 4.6.3Inflation pressure The inflation pressure of the test tyre at ambient temperature shall be the inflation pressure, specified by the tyre manufacturer concerned, corresponding to the maximum single tyre load capacity. The pressure shall be capped. 4.7Rims The rims used in the test should be of a size and type approved by the tyre manufacturer for use with the test tyre. If such rims are not available, or if the information is unknown, a standard measuring rim, or the rim nearest in size and type to it, shall be used in the test. 4.8Procedure 4.8.1To ensure repeatability of measurements, an initial break-in and cooling period can be necessary prior to the start of the test. Such a break-in should be carried out on a test drum of at least in diameter, for a period of at least , at the reference test speed of or , whichever applies in accordance with 4.4, with the load and inflation pressure as specified in 4.6.1 and 4.6.3 respectively. 4.8.2For future comparisons, record the overall diameter of the new tyre after the break-in. 4.8.3Allow the tyre to stand, inflated, in the test area thermal environment in order for it to achieve thermal equilibrium, generally reached after . 4.8.4Adjust the inflation pressure to that specified in 4.6.3. After about , verify that the load is as specified in 4.6.1. 4.8.5Rotate the drum at the test speed for at least , in order to warm up the tyre and reach thermal equilibrium. 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. 4.8.6Record the number of revolutions (and portions thereof) of both tyre and drum that occur during a time duration, . For tyre as well as for drum, the total number of impulses during the time should be greater than 1 000. Ni 85 % 1,7 m 1 h60 km/h80 km/h 6 h 10 min 90 min TT Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) 4© ISO 2008 All rights reserved 4.9Calculation Calculate the rolling circumference of the test tyre, , in millimetres, as follows: where is the number of revolutions of the drum; is the number of revolutions of the tyre; is the radius of the drum, in millimetres. 5Test method using vehicle 5.1Principle This method consists of driving a typical vehicle equipped with the test tyres on the drive axle, on a straight, level, paved road at a constant speed, and counting the number of tyre revolutions (or portions thereof) that occur while traversing an accurately measured distance. 5.2Test course The test course shall be a level, straight section of smooth, dry road surfaced with either asphalt or concrete pavement of medium roughness. The longitudinal and transverse gradient of the road shall be at most . The length of the course should be or longer, depending on the accuracy of the test equipment as specified in 5.5. The length of the test course, expressed in metres, shall be measured to within . 5.3Test temperature and wind speed The ambient temperature shall be between and . However, an asphalt surface shall be sufficiently cool so that the surface is not tacky. The wind speed shall not exceed . 5.4Test speed 5.4.1Test speed for load index 122 and above The speed shall be for tyres with speed symbols K to M inclusive, and for speed symbols F to J inclusive. For tyres that bear the mandatory marking “max. speed ” or “max. speed ”, and for tyres not marked with a speed symbol, the test speed shall be . 5.4.2Test speed for load index 121 and below The test speed shall be . NOTEThis also applies to tyres without a speed symbol on the sidewall. Cr Cr=2 (Nd/Nt)R Nd Nt R 1 % 500 m 0,1 % 5 C 30 C 3 m/s 80 km/h±2 km/h60 km/h±2 km/h 55 mph/88 km/h50 mph/80 km/h 60 km/h±2 km/h 80 km/h±2 km/h Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:38:45 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 9112:2008(E) © ISO 2008 All rights