ISO 4251-1:2019 農業用トラクター、トレーラー、機械用のコード指定斜めタイヤ（プライ定格マーク付きシリーズ）—パート1：タイヤの指定と寸法、および承認されたリムの輪郭 | ページ 2

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.

The procedures used to develop this document and those intended for its further maintenance are described in the 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 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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of 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.

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This document was prepared by Technical Committee ISO/TC 31, Tyres, rim and valves, Subcommittee SC 5, Agricultural tyres and rims.

This eighth edition cancels and replaces the seventh edition (ISO 4251-1:2017), which has been technically revised. The main changes compared to the previous edition are as follows:

• information already contained in other International Standards was removed and replaced with normative references to those standards;
• radial tyres marked with ply rating and with a reference speed of 10 km/h were deleted since obsolete and this document was restricted to code designated diagonal tyres (marked with PR) for agricultural tractors, trailers and machines;
• the title of this document was revised accordingly;
• the document was aligned with other International Standards developed by SC 5 and with existing regulations;
• additional definitions useful for the comprehension of this document were added;
• specific markings for tractor steering wheel and implement tyres and the pictogram to identify the maximum pressure for tyre bead seating, as specified by UN/ECE Regulation 106, were introduced;
• dimensional data and the list of approved rim contours were revised.

1 Scope

This document establishes the designation in use and the dimensions of code designated tyres in diagonal construction (ply rating marked series) for agricultural tractors, trailers and machines.

Tyre load ratings are given in ISO 4251-2.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4223-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography