ISO 4210-5:2023

Cycles - Safety requirements for bicycles - Part 5: Steering test methods

This document specifies the steering test methods for ISO 4210‑2.

Cycles — Exigences de sécurité pour les bicyclettes — Partie 5: Méthodes d'essai de la direction

Le présent document spécifie les méthodes d'essai de la direction pour l'ISO 4210-2.

General Information

• Status: Published
• Publication Date: 10-Jan-2023
• ICS: 43.150 - Cycles
• Technical Committee: ISO/TC 149/SC 1 - Cycles and major sub-assemblies
• Drafting Committee: ISO/TC 149/SC 1/WG 13 - Revision of the series of ISO 4210:2014 and ISO 8098:2014
• Current Stage: 6060 - International Standard published
• Start Date: 11-Jan-2023
• Due Date: 12-Sep-2022
• Completion Date: 11-Jan-2023

Relations

• Revises: ISO 4210-5:2014 - Cycles - Safety requirements for bicycles - Part 5: Steering test methods
• Effective Date: 23-Apr-2020

Overview

ISO 4210-5:2023 - "Cycles - Safety requirements for bicycles - Part 5: Steering test methods" specifies standardized steering and handlebar test methods that support ISO 4210‑2 requirements for city, trekking, young adult, mountain and racing bicycles. This second edition (2023) updates test procedures used to verify the strength, durability and secure assembly of handlebars, stems, grips, bar ends and related steering components.

Key topics and technical requirements

This part of the ISO 4210 series defines practical steering test methods, including:

• Handlebar grips and plugs

  • Freezing test: grips/plugs immersed then frozen; 70 N loosening force applied until +5 °C.
  • Hot water test: immersion at +60 °C ±2 °C for 1 h; 100 N loosening force maintained 1 min.

• Handlebar stem and assembly bending tests

  • Stem lateral bending (quill or extension): lateral force F at distance d (see standard). Example forces: 600 N (city/trekking, young adult), 1 000 N (mountain, racing).
  • Handlebar + stem lateral bending: force applied 50 mm from free end; forces aligned with ISO tables.

• Forward bending (stem)

  • Stage 1: apply force at 45°; 1 600 N for all bicycle types; measure permanent deformation per ISO 4210‑2.
  • Stage 2: progressively increase to higher forces (e.g., 2 000–2 600 N) or until specified deflection.

• Torsional security tests

  • Handlebar-to-stem torque: 60–80 N·m depending on bicycle type.
  • Stem-to-steerer torque: 50 N·m applied in each rotation direction.
  • Bar end torsion: forces specified by bar‑end length (example forces: 300–500 N).

• Other tests

  • Torsional tests for bar ends and aerodynamic extensions, and fatigue tests for handlebar/stem assemblies (including special procedure for drop handlebars).

All test values and procedures are normative and referenced to ISO 4210‑2 and ISO 4210‑3 for common test methods and definitions.

Practical applications and who uses it

ISO 4210-5:2023 is used by:

• Bicycle manufacturers for design verification and production quality control
• Component suppliers (stems, handlebars, grips, bar ends) for product validation
• Accredited test laboratories performing conformity and safety testing
• Product development and R&D teams to assess durability and rider safety
• Regulatory bodies and procurement specialists specifying safety compliance

Adoption of these steering test methods reduces steering-failure risks, supports conformity with ISO 4210‑2 safety requirements, and helps manufacturers demonstrate product reliability.

Related standards

• ISO 4210-1: Vocabulary (definitions)
• ISO 4210-2: Requirements for city, trekking, young adult, mountain and racing bicycles
• ISO 4210-3: Common test methods

ISO 4210-5:2023 is essential when implementing ISO 4210 bicycle safety testing and for anyone concerned with handlebar and steering component safety, torsional security, bending resistance and fatigue performance.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4210-5
Second edition
2023-01
Cycles — Safety requirements for
bicycles —
Part 5:
Steering test methods
Cycles — Exigences de sécurité pour les bicyclettes —
Partie 5: Méthodes d'essai de la direction
Reference number
© ISO 2023
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test methods . 1
4.1 Handlebar grips and plugs . 1
4.1.1 Freezing test . 1
4.1.2 Hot water test . 2
4.2 Handlebar stem — Lateral bending test . 2
4.3 Handlebar and stem assembly — Lateral bending test . 3
4.4 Handlebar stem — Forward bending test . 5
4.4.1 Test method for stage 1 . 5
4.4.2 Test method for stage 2 . 7
4.5 Handlebar to handlebar stem — Torsional security test . 7
4.6 Handlebar stem to fork steerer — Torsional security test . 7
4.7 Bar end to handlebar — Torsional security test . 8
4.8 Aerodynamic extensions to handlebar — Torsional security test . 9
4.9 Handlebar and stem assembly — Fatigue test . 10
4.9.1 Test method except drop handlebar . 10
4.9.2 Test method for drop handlebar .12
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 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.
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 149, Cycles, Subcommittee SC 1, Cycles
and major sub-assemblies, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 333, Cycles, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 4210-5:2014), which has been technically
revised.
The main changes are as follows:
— improvement of 4.1.1;
— improvement of 4.3;
— improvement of 4.4;
— increase in test torque for 4.6;
— improvement of 4.9.
A list of all parts in the ISO 4210 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
Introduction
This document has been developed in response to demand throughout the world, and the aim has been
to ensure that bicycles manufactured in conformity with this document will be as safe as is practically
possible. The tests have been designed to ensure the strength and durability of individual parts as well
as of the bicycle as a whole, demanding high quality throughout and consideration of safety aspects
from the design stage onwards.
The scope has been limited to safety considerations, and has specifically avoided standardization of
components.
If the bicycle should be used on public roads, national regulations apply.
v
INTERNATIONAL STANDARD ISO 4210-5:2023(E)
Cycles — Safety requirements for bicycles —
Part 5:
Steering test methods
1 Scope
This document specifies the steering test methods for ISO 4210-2.
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.
ISO 4210-1, Cycles — Safety requirements for bicycles — Part 1: Vocabulary
ISO 4210-2:2023, Cycles — Safety requirements for bicycles — Part 2: Requirements for city and trekking,
young adult, mountain and racing bicycles
ISO 4210-3:2023, Cycles — Safety requirements for bicycles — Part 3: Common test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4210-1 apply.
ISO and IEC maintain terminological 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 Test methods
4.1 Handlebar grips and plugs
4.1.1 Freezing test
Immerse the handlebar, with handlebar grips or plugs fitted, in water at room temperature for 1 h and
then place the handlebar in a freezer until the handlebar is at a temperature lower than −5 °C. Remove
the handlebar from the freezer and allow the temperature of the handlebar to reach −5 °C, and then
apply a force of 70 N to the grip or plug in the loosening direction as shown in Figure 1. Maintain the
force until the temperature of the handlebar has reached +5 °C. It shall be permitted to create a hole in
the plug to allow for the testing fixture to be fitted so long as the hole does not affect the seat of the plug
in the handlebar and the fixture does not contact the handlebar during the test.
Temperature is measured on the handlebar 3 cm from the grip towards the centre of the handlebar.
Key
1 handlebar grip
2 handlebar
3 drawing attachment
4 hooking ring
5 clearance
F force
NOTE The hooking ring can be divided.
Figure 1 — Example of handlebar grip drawing attachment
4.1.2 Hot water test
Immerse the handlebar, with handlebar grips fitted, in hot water of +60 °C ± 2 °C for 1 h. Remove the
handlebar from the hot water, allow the handlebar to stabilize at ambient temperature for 30 min, and
apply a force of 100 N to the grip in the loosening direction as shown in Figure 1. Maintain this force for
1 min.
4.2 Handlebar stem — Lateral bending test
For stems which have a quill for insertion into a fork steerer, clamp the quill securely in a fixture to
the minimum insertion depth as specified in ISO 4210-2:2023, 4.7.3, or for stem extensions which
clamp directly on to an extended fork steerer, attach the extension to a fork steerer according to the
manufacturer's instructions and clamp this fork steerer securely in a fixture to the appropriate height.
Assemble a straight test bar to the stem, and apply a force of F at a distance of d laterally from the axis
of the stem as shown in Table 1 and Figure 2. Maintain this force for 1 min.
Table 1 — Forces and distances on handlebars
City and trekking
Bicycle type Young adult bicycle Mountain bicycle Racing bicycle
bicycle
Force, F
600 600 1 000 1 000
N
Distance, d
300 300 300 230
mm
a)  Combined stem and quill b)  Stem extension
Key
1 minimum insertion depth
2 clamping block
3 solid-steel bar
d distance
F force
Figure 2 — Handlebar stem — Lateral bending test
4.3 Handlebar and stem assembly — Lateral bending test
Assemble the handlebar and stem in accordance with the manufacturer's instructions. Align the grips
portion of the handlebar in a plane perpendicular to the steerer axis [see Figure 3 a) or Figure 4 a)].
If perpendicular alignment is not achievable within the manufacturer’s recommended range, then the
alignment shall be as close as possible. If perpendicular alignment is achievable in multiple positions,
or for stems with adjustable length or angle, fix the stem and handlebar in positions resulting in the
maximum bending moment with respect to the steerer axis. For permanently connected handlebar and
stem, e.g. by welding or brazing, install per manufacturer's instructions. For stems which have a quill
for insertion into a fork steerer, clamp the quill securely in a fixture to the minimum insertion depth, or
for stem extensions which clamp directly on to an extended fork steerer, attach the extension to a fork
steerer according to the manufacturer's instructions and clamp this fork steerer securely in a fixture
to the appropriate height. Apply a force of F (see Table 2) at a distance of 50 mm from the free end of
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