ISO/FDIS 25408-2

• Status: Not Published
• ICS: 77.140.65 - Steel wire, wire ropes and link chains
• ICS: 83.140.01 - Rubber and plastics products in general
• ICS: 83.160.01 - Tyres in general
• Technical Committee: ISO/TC 17/SC 17 - Steel wire rod and wire products
• Drafting Committee: ISO/TC 17/SC 17 - Steel wire rod and wire products
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 26-Aug-2026
• Completion Date: 26-Aug-2026

ISO/FDIS 25408-2 is an ISO draft International Standard for testing the adhesion of bead wire to vulcanized rubber compounds. It specifies a pull-out test, and it also covers an optional visual check of rubber coverage on the pulled specimen, for bead wire test work in laboratories and quality control.

What does ISO/FDIS 25408-2 specify?

ISO/FDIS 25408-2 specifies a test method for the strength of adhesion of round and shaped bead wire to vulcanized rubber compounds. The document is aimed at producing comparable pull-out force results, and it also provides a way to assess rubber coverage rate (RCR) when visual evaluation is needed.

The document is organized into scope, normative references, terms and definitions, principle, apparatus, procedure, calculation and report of pull-out force, precision and variance, rubber coverage rate, and calculation and report of RCR. In practice, that structure takes the reader from test setup through specimen preparation, vulcanization, cleaning, testing, and reporting.

What are the key requirements of ISO/FDIS 25408-2?

ISO/FDIS 25408-2 puts most of its technical detail into the test setup and the sequence of preparation steps. The practical effect is that adhesion results depend not only on the tensile test, but also on mould design, rubber handling, curing control, and timing.

Test principle and test setup

ISO/FDIS 25408-2 measures the force needed to pull bead wire linearly out of a vulcanized rubber block. The block holder uses a circular hole to help keep the stress distribution uniform, which matters because uneven loading can distort the result.

The tensile testing machine is a constant-rate-of-extension (CRE) machine with load measurement, extension recording, and data logging or equivalent output. The vulcanization press, mould, and block holder are all specified so that specimen geometry and curing conditions are controlled rather than left to local practice.

Specimen preparation and vulcanization

ISO/FDIS 25408-2 describes two preparation routes: a hot moulding method and a pre-building mould method. Both require careful handling of the bead wire and rubber sheets so the contact surfaces are not contaminated, because surface contamination can change adhesion.

The document also uses reference material to monitor the stability of the vulcanization process. In practice, that means the user can check whether changes in measured adhesion come from the process or from the material being tested.

Pull-out test and reporting

ISO/FDIS 25408-2 requires the trimmed rubber block to be mounted so each specimen is centered in the block holder and tested at a controlled pull-out rate. The maximum force is recorded, and results are reported as the average pull-out force for each sample group.

This matters because the method reports both individual specimen behavior and a grouped result for each sample, which is how production lots are usually compared in quality work.

Precision and rubber coverage rate

ISO/FDIS 25408-2 expresses method variability as coefficient of variation (CV) and gives maximum acceptable CV values by bead wire diameter. It also says CV evaluation should be based on controlled cross checks or measurement system analysis (MSA) studies, so the precision data are used for method control rather than as a routine single-test check.

For visual inspection, ISO/FDIS 25408-2 defines rubber coverage rate (RCR) by judging how much of the wire surface remains covered after pull-out. The method uses magnification and extra light, and the result is reported as an average RCR per sample, with an additional coded report range if needed.

What terms does ISO/FDIS 25408-2 define?

• Bead wire - The wire tested for adhesion to rubber; ISO 16650 supplies the terms and definitions used in this document.
• CRE - Constant-rate-of-extension, the tensile testing mode used to pull the specimen at a controlled rate.
• POF - Pull-out force, the maximum force recorded when a bead wire specimen is pulled out of the rubber block.
• CV - Coefficient of variation, used here to express test method variance relative to the mean result.
• RCR - Rubber coverage rate, a visual measure of how much rubber remains on the pulled wire surface.
• MSA - Measurement system analysis, used as a basis for evaluating whether the adhesion test variability is under control.
• RM - Reference material, a stable material used to monitor vulcanization process stability.

Who uses ISO/FDIS 25408-2?

ISO/FDIS 25408-2 is used by laboratories, test technicians, and quality teams that check bead wire adhesion to vulcanized rubber. It is also relevant to bead wire suppliers and users who need a repeatable way to compare pull-out force and, when required, rubber coverage after testing.

The document is especially useful where rubber compound preparation, vulcanization control, and test reporting must be consistent across different labs or production sites. That makes it a practical method for incoming inspection, process monitoring, and product qualification work.

Which standards are used with ISO/FDIS 25408-2?

ISO/FDIS 25408-2 cites ISO 16650, Bead wire, for the terms and definitions used in the document. That reference supports the common language for the wire being tested and helps keep test reports consistent.

What does the ISO/FDIS 25408-2 document contain?

ISO/FDIS 25408-2 contains equipment requirements for the tensile machine, vulcanization press, mould, block holder, solvent handling, rubber cutter, and consumables. It also contains step-by-step procedures for rubber preparation, mould preparation, specimen preparation, rubber block building, cleaning, and the pull-out test.

The document includes a calculation and reporting method for pull-out force, a precision section based on CV, and a separate section for RCR evaluation. It also includes a table of maximum acceptable CV by bead wire diameter and a reporting code for RCR ranges.

Several figures support the procedures, including the vulcanization mould, block holder, rubber block, sample distribution, and cleaning of the rubber block. Those figures are there to show specimen position, geometry, and handling details that affect the test result in practice.

FINAL DRAFT
International
Standard
ISO/TC 17/SC 17
Testing method for bead wire —
Secretariat: SAC
Part 2:
Voting begins on:
2026-08-26
Adhesion test
Voting terminates on:
Méthode d'essai pour les fils de tringle —
2026-10-21
Partie 2: Essai d'adhérence
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 17/SC 17
Testing method for bead wire —
Secretariat: SAC
Part 2:
Voting begins on:
Adhesion test
Voting terminates on:
Méthode d'essai pour les fils de tringle —
Partie 2: Essai d'adhérence
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.1 Tensile testing machine .1
5.2 Vulcanization press .2
5.3 Mould .2
5.4 Block holder .3
5.5 Rubber pad remover and pressure roll .3
5.6 Solvent .3
5.7 Rubber cutter .4
5.8 Consumable .4
5.8.1 Rubber compound .4
5.8.2 Mould release lubricant: .4
6 Procedure . 4
6.1 Preparation for rubber compound .4
6.2 Preparation for vulcanization mould .4
6.3 Sample preparation .5
6.4 Preparation of the rubber block .5
6.4.1 Hot moulding method .5
6.4.2 Pre-building mould method .6
6.5 Cleaning process .8
6.6 Pull out test .8
7 Calculation and report of pull-out force . 9
8 Precision and variance . 9
9 Rubber coverage rate (RCR) . 9
10 Calculation and report of rubber coverage rate (RCR) .10

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.
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 17, Steel wire rod
and wire products.
A list of all parts in the ISO 25408 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
FINAL DRAFT International Standard ISO/FDIS 25408-2:2026(en)
Testing method for bead wire —
Part 2:
Adhesion test
1 Scope
This document specifies the test method for strength of adhesion of bead wire (round and shaped) to
vulcanized rubber compounds.
The method applies to, but is not limited to, wire made from brass, bronze, or zinc coated steel wire.
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.
ISO 16650, Bead wire
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16650 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
Specimens of bead wire are vulcanized into a block of rubber and force necessary to pull bead wires that are
linearly out of the rubber is measured. The used clamp or block holder shall be equipped with a circle hole to
guarantee the homogenous stress. If required, the visual evaluation of rubber coverage is also determined.
5 Apparatus
5.1 Tensile testing machine
a) The constant-rate-of-extension (CRE) tensile testing machine capacity that the measured force is
required to fracture the wire shall be within force measurement range. The device shall be equipped
with a load and extension recorder, digital read-out, automated data logger or computer controlled
tensile test machine.
b) Cross-head speed: maximum speed shall be ≥ 150 mm/min. (≠ test speed).
c) Machine accuracy Class 0,5 = Load weighing accuracy: ± 0,5 %.
d) Load cell capacity depends on the type and characteristics of the wire.

5.2 Vulcanization press
a) The machine type of vulcanization press can be electrical or steam heat which is large enough to take
the mould dimensions and capable of a minimum pressure of 3,5 MPa over the total area of the mould
plate used.
b) Dimension of the press platens: minimum 400 mm × 400 mm.
c) Temperature capacity: maximum 200 °C.
d) For a standard 1 cavity mould (50 mm embed) a pressure of 70 kN to 100 kN is to apply.
e) Heating for the top and the bottom platens shall be of sufficient capacity for maintaining the mould
components at the specific temperatures required for the rubber compound being used.
f) The heat up power of the press shall be min 10 °C/min or better 20 °C/min.
g) Temperature resolution: 0,5 °C.
h) Temperature in the rubber shall be controlled within ±2 °C during vulcanization.
5.3 Mould
a) Mould designed for a 13 mm thick block of rubber, 222 mm long, and 50 mm wide, with 15 wire slots
across the width of the mould spaced 13 mm apart at the middle of the mould thickness, and with top
and bottom plates for the mould.
b) Moulds with embed lengths of 12,5 mm ,15 mm , 20 mm or 25 mm may be used, as specified and agreed
by relevant parties.
c) The 15 wire slots have a typical ‘Y’ shape groove for bead wire adhesion testing.
d) The ‘Y’ shape slot width can be according to wire thickness. Standard slot widths are 1,15 mm and
2,1 mm and 3,1 mm. Standard depth of ‘Y’ shape slots is 7,5 mm (see Figure 1).
Figure 1 — Vulcanization mould

5.4 Block holder
The block holder grip shall be a special holder made for the vulcanized block sample. The opposite grip may
be any type of clamp of sufficient capacity to handle the specimen and designed to prevent its slippage in the
grip area (see Figure 2).
NOTE 1 The dimensions all with accuracy ±0,2 mm except where noted.
NOTE 2 Material is steel.
NOTE 3 Break all sharp corners.
Figure 2 — Block holder
5.5 Rubber pad remover and pressure roll
Rubber pad remover or
...

ISO/TC 17/SC 17
Secretariat: SAC
Date: 2026-06-2908-12
Testing method for bead wire – —
Part 2:
Adhesion test
Méthode d'essai pour les fils de tringle —
Partie 2: Essai d'adhérence
FDIS stage
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
5.1 Tensile testing machine . 1
5.2 Vulcanization press . 2
5.3 Mould . 2
5.4 Block holder . 3
5.5 Rubber pad remover and pressure roll . 5
5.6 Solvent . 5
5.7 Rubber cutter . 6
5.8 Consumable . 6
6 Procedure . 6
6.1 Preparation for rubber compound . 6
6.2 Preparation for vulcanization mould . 7
6.3 Sample preparation . 7
6.4 Preparation of the rubber block. 7
6.5 Cleaning process . 11
6.6 Pull out test . 12
7 Calculation and report of pull-out force . 12
8 Precision and variance. 12
9 Rubber coverage rate (RCR) . 13
10 Calculation and report of rubber coverage rate (RCR) . 14

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.
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 document 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).
Field Code Changed
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
Field Code Changed
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 17, Steel wire rod
and wire products.
A list of all parts in the ISO 25408 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
Field Code Changed
iv
Testing method for bead wire – —
Part 2:
Adhesion test
1 Scope
This document specifies the test method for strength of adhesion of bead wire (round and shaped) to
vulcanized rubber compounds.
The method applies to, but is not limited to, wire made from brass, bronze, or zinc coated steel wire.
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.
ISO 16650, Bead wire
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16650 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Principle
Specimens of bead wire are vulcanized into a block of rubber and force necessary to pull bead wires that are
linearly out of the rubber is measured. The used clamp or block holder shall be equipped with a circle hole to
guarantee the homogenous stress. If required, the visual evaluation of rubber coverage is also determined.
5 Apparatus
5.1 Tensile testing machine
a) a) The constant-rate-of-extension (CRE) tensile testing machine capacity that the measured force
is required to fracture the wire shall be within force measurement range. The device shall be equipped
with a load and extension recorder, digital read-out, automated data logger or computer controlled tensile
test machine.
b) b) Cross-head speed: maximum speed shall be ≥ 150 mm/min. (≠ test speed)).
c) c) Machine accuracy Class 0,5 = Load weighing accuracy: +/-± 0,5 %%.
d) d) Load cell capacity depends on the type and characteristics of the wire.
5.2 Vulcanization press
a) a) The machine type of vulcanization press can be electrical or steam heat which is large enough
to take the mould dimensions and capable of a minimum pressure of 3,5 MPa over the total area of the
mould plate used.
b) b) Dimension of the press platens: minimum 400 mm x× 400 mm.
c) c) Temperature capacity: maximum 200 °C.
d) d) For a standard 1 cavity mould (50 mm embed) a pressure of 70 kN to 100 kN is to apply.
e) e) Heating for the top and the bottom platens shall be of sufficient capacity for maintaining the
mould components at the specific temperatures required for the rubber compound being used.
f) f) The heat up power of the press shall be min 10 °C/min or better 20 °C/min.
g) g) Temperature resolution: 0,5 °C.
h) h) Temperature in the rubber shall be controlled within ±2 °C during vulcanization.
5.3 Mould
a) a) Mould designed for a 13 mm thick block of rubber, 222 mm long, and 50 mm wide, with 15
wire slots across the width of the mould spaced 13 mm apart at the middle of the mould thickness, and
with top and bottom plates for the mould.
b) b) Moulds with embed lengths of 12,5 mm ,15 mm , 20 mm or 25 mm may be used, as specified
and agreed by relevant parties.
c) c) The 15 wire slots have a typical ‘Y’ shape groove for bead wire adhesion testing.
d) d) The ‘Y’ shape slot width can be according to wire thickness. Standard slot widths are 1,15 mm
and 2,1 mm and 3,1 mm. Standard depth of ‘Y’ shape slots is 7,5 mm (see Figure 1Figure 1).).
Figure 1 — Vulcanization mould
5.4 Block holder
The block holder grip shall be a special holder made for the vulcanized block sample. The opposite grip may
be any type of clamp of sufficient capacity to handle the specimen and designed to prevent its slippage in the
grip area (see Figure 2Figure 2).).
Key
NOTE 1 The dimensions all with accuracy ±0.,2 mm except where noted.
NOTE 2 Material is steel.
NOTE 3 Break all sharp corners.
Figure 2 — Block holder
5.5 Rubber pad remover and pressure roll
Rubber pad remover or manual mould ejector is recommended for safely and quickly removing of rubber
block out of the hot mould without extreme bending of the ongoing adhesion pad.
5.6 Solvent
a) a) The use of solvent on rubber surface or bead wire surface can influence the adhesion process.
b) b) Cleaning or even touching rubber surface and bead wire surface is not allowed.
c) c) Only if the requester really requires cleaning the rubber surface or the bead wire surface is it
allowed.
d) d) The re-freshening action shall take place at least 10 minutes prior to the pad assembly.
e) e) A suitable solvent has been found to be lead-free gasoline (normal heptane’s), with a
distillation range from 40 °C to 141 °C and a maximum recovery of 97 %, available from most solvent
suppliers.
5.7 Rubber cutter
a) a) The rubber cutter shall be able to cut rubber with a thickness of 7 mm with acceptable
precision to achieve correct rubber sheath dimensions.
b) b) A big paper cutter or clicker dies with exact target dimensions are to be used.
5.8 Consumable
5.8.1 Rubber compound
a) a) The rubber compound can be provided in sheath form, 7 mm thick on a non-hygroscopic
backing, such as a plasticizer free plastic material, or may be provided un-milled in a form requiring
milling immediately prior to use.
b) b) The rubber compound shall be provided together with information on storage conditions and
shelf - life. If no specific requirements are specified by agreement between relevant parties, the storage
conditions and shelf - life shall comply with the following requirements:
1) 1) The rubber compound shall be stored in the laboratory environment with a temperature of
(23 ± 5) °C and a humidity of (40- to 55) % RH. I
...