ISO 11407:2004

Commercial road vehicles - Mechanical coupling between towing vehicles, with coupling mounted forward and below, and centre-axle trailers - Interchangeability

ISO 11407:2004 specifies the interchangeability requirements -- the various elements and dimensions -- for the mechanical coupling of towing vehicles whose coupling is mounted forward and below to centre-axle trailers. It is applicable to road trains for the commercial transport of low-density, high-volume cargo of the greatest possible variety. It is also applicable to corresponding equipment in cases where the same vehicle makes up part of a road train having more than one trailer. It is not applicable to dedicated or special combinations such as coupling systems with an extensible drawbar; nor does it specify limitations on maximum gross mass and overall dimensions, which are generally laid down by legislative requirements.

Véhicules routiers utilitaires — Accouplement mécanique entre véhicules tracteurs à dispositif d'attelage avancé et surbaissé et remorques à essieux centraux — Interchangeabilité

General Information

• Status: Published
• Publication Date: 28-Oct-2004
• ICS: 43.040.70 - Couplings
• Technical Committee: ISO/TC 22/SC 40 - Specific aspects for light and heavy commercial vehicles, busses and trailers
• Drafting Committee: ISO/TC 22/SC 40 - Specific aspects for light and heavy commercial vehicles, busses and trailers
• Current Stage: 9093 - International Standard confirmed
• Start Date: 03-Mar-2021
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 11407:1993 - Commercial road vehicles - Mechanical coupling between towing vehicles with coupling mounted forward and below, and centre-axle trailers - Interchangeability
• Effective Date: 15-Apr-2008

Overview

ISO 11407:2004 - "Commercial road vehicles - Mechanical coupling between towing vehicles, with coupling mounted forward and below, and centre-axle trailers - Interchangeability" specifies dimensional and interchangeability requirements for mechanical drawbar couplings used between towing vehicles (with the coupling mounted forward and below) and centre-axle trailers. The standard targets road trains carrying low‑density, high‑volume cargo and covers the geometry, classes and marking needed to ensure safe, interchangeable coupling across manufacturers and operators.

Key topics and requirements

• Interchangeability dimensions - Defines the key parameter A (distance between drawbar coupling axis and rear end of towing vehicle) in class values: 1 400 mm, 1 600 mm, 1 900 mm (low/high classes).
• Turning front (C) - Minimum front clearance C is calculated from vehicle width (W), A and a minimum safety clearance S. Practical form:
  • C_min = sqrt(A^2 + (W/2)^2) + S
  • Recommended minimum S = 250 mm (365 mm gives additional margin).
• Coupling heights and drawbar contour - Specifies coupling and towing‑eye heights for laden vehicles and drawbar geometry. Notes that drawbar‑eye dimensions reference ISO 1102, though centre‑axle trailers may need reinforced eyes.
• Rear end configurations - Distinguishes high and low rear‑end classes (low for vehicles fitted with tail lifts or extra equipment). Figures define permissible contours and clearances.
• Angles and articulation - Requires no contact for inclination α up to 6°; articulation angle β up to 90° must be permitted under manoeuvring.
• Marking - Vehicles and trailers should carry a permanent 150 × 150 mm plate indicating class/dimension A to ensure easy recognition and correct matching.
• Scope limits - Not applicable to dedicated/special combinations (e.g., extensible drawbars), nor does it set gross mass or overall dimension limits (these are legislative).

Applications and users

• Who uses it:
  • Vehicle and trailer manufacturers, chassis and drawbar designers
  • Fleet operators and logistics companies specifying interchangeable road train equipment
  • Type‑approval bodies, procurement teams and test laboratories
• Practical uses:
  • Designing centre‑axle trailers and towing vehicles to be interoperable across fleets
  • Specifying coupling geometry to avoid interference with tail lifts and overhang equipment
  • Ensuring safe clearance and articulation for mixed combinations and multi‑trailer road trains

Related standards

• ISO 1102 - 50 mm drawbar eye interchangeability (referenced for drawbar‑eye dimensions)
• ISO 11406 - Mechanical coupling for rear‑mounted couplings and drawbar trailers (different coupling location)

Keywords: ISO 11407:2004, commercial road vehicles, mechanical coupling, centre‑axle trailers, drawbar coupling, interchangeability, drawbar eye, road train.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11407
Second edition
2004-11-01
Commercial road vehicles — Mechanical
coupling between towing vehicles, with
coupling mounted forward and below,
and centre-axle trailers —
Interchangeability
Véhicules routiers utilitaires — Accouplement mécanique entre
véhicules tracteurs à dispositif d'attelage avancé et surbaissé et
remorques à essieux centraux — Interchangeabilité

Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Interchangeability dimensions . 1
2.1 Distance between drawbar coupling axis and rear end of towing vehicle . 1
2.2 Turning front of trailer . 2
2.3 Height of couplings. 3
2.4 Drawbar contour . 3
2.5 Rear end of towing vehicle . 3
2.6 Angles of inclination and articulation. 3
3 Possible combinations and marking . 5
Annex A (informative) Classes of dimensions for C . 7
min
Annex B (informative) Vehicle combinations — Examples of configurations . 8
Bibliography . 9

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 11407 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 15,
Interchangeability of components of commercial vehicles and buses.
This second edition cancels and replaces the first edition (ISO 11407:1993), which has been technically
revised.
iv © ISO 2004 – All rights reserved

Introduction
In many countries, the total length of road trains is limited by law. In view of the increasing demand for
large-volume transports, vehicle manufacturers have developed solutions for optimizing the loading space of
road trains within the legal specification. Centre-axle trailers are a well-proven means of reducing the
necessary free space between towing vehicles and trailer, thereby increasing loading space while keeping
within legal limitations.
New demands, wider usage and further development of the concept have lead to further changes. To increase
the volume even more, lower vehicle chassis have been developed. There is also a growing demand for extra
equipment in the overhang, such as retractable tail lift and additional drawbar coupling fitted in the end of the
chassis frame.
In order to prevent interference between the drawbar and this extra equipment, specifically on low chassis, it
has become necessary to introduce a new, “low” class of drawbar profile.
A new category of road train (25,25 m) has been introduced in Finland and Sweden, the intention being that it
will be possible to couple vehicles conforming with this International Standard to combinations of more than
one trailer. Consequently, this edition of ISO 11407 is applicable to drawbar and drawbar coupling positions
on those road trains, as well.

INTERNATIONAL STANDARD ISO 11407:2004(E)

Commercial road vehicles — Mechanical coupling between
towing vehicles, with coupling mounted forward and below, and
centre-axle trailers — Interchangeability
1 Scope
This International Standard specifies the interchangeability requirements of the various elements and
dimensions for the mechanical coupling of towing vehicles whose coupling is mounted forward and below to
centre-axle trailers. It is applicable to road trains for the commercial transport of low-density, high-volume
cargo of the greatest possible variety. It is also applicable to corresponding equipment in cases where the
same vehicle makes up part of a road train having more than one trailer. It is not applic
...