ISO 11795:1997

INTERNATIONAL ISO
STANDARD 11795
First edition
1997-12-15
Agricultural tractor drive wheel tyres —
Method of measuring tyre rolling
circumference
Pneumatiques pour roues motrices de tracteurs agricoles — Méthode de
mesure de la circonférence de roulement
A
Reference number
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 11795 was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves,
Subcommittee SC 5, Agricultural tyres and rims.
Annex A of this International Standard is for information only.
©  ISO 1997
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 the publisher.
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Printed in Switzerland
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ISO ISO 11795:1997(E)
Introduction
Matching front and rear wheels with different tyre sizes on four-wheel drive agricultural tractors requires accurate
rolling circumference values. The test method to determine rolling circumference outlined below was developed to
follow this requirement. The values thus obtained are not intended for use as levels of performance or quality.
The test speed has been set at typical working speed when the four-wheel drive will likely be engaged and the most
critical match is required. Generally, the four-wheel drive is disengaged at roading speeds. Therefore, the
determination of rolling circumference is not related to the tyre's maximum speed, e.g. 30 km/h or 40 km/h.
Nevertheless, other speeds or conditions may be run provided it is clearly documented in the results.
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INTERNATIONAL STANDARD  ISO ISO 11795:1997(E)
Agricultural tractor drive wheel tyres — Method of
measuring tyre rolling circumference
1 Scope
This International Standard specifies the method for measuring rolling circumference for new tyres, under loaded
conditions, made for use on agricultural tractors and machines, and applies to agricultural tractor drive wheel tyres
in diagonal and radial construction.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
1)
ISO 4251-1:— , Tyres (ply rating marked series) and rims for agricultural tractors and machines — Part 1: Tyre
designation and dimensions, and approved rim contours.
2)
ISO 4251-2:— , Tyres (ply rating marked series) and rims for agricultural tractors and machines — Part 2: Tyre load
ratings.
ISO 7867-1:1996, Tyres and rims (metric series) for agricultural tractors and machines — Part 1: Tyre designation,
dimensions, marking and tyre/rim coordination.
ISO 7867-2:1996, Tyres and rims (metric series) for agricultural tractors and machines — Part 2: Service
description and load ratings.
ISO 8664:1992, Agricultural tractor drive-wheel tyres — Service description (load index - speed symbol) marked
tyres.
3 Definition
For the purposes of this International Standard, the following definition applies.
3.1 rolling circumference of tyre
distance that the (axle) centre of the tyre moves in one revolution of the tyre under the conditions specified in
clause 5
4 Principle
The measurement consists of driving a typical vehicle equipped with the test tyres on the drive axle, on a straight,
level road at a constant speed, and counting the number
...