ISO 11406:2001
(Main)Commercial road vehicles - Mechanical coupling between towing vehicles with rear-mounted coupling and drawbar trailers - Interchangeability
Commercial road vehicles - Mechanical coupling between towing vehicles with rear-mounted coupling and drawbar trailers - Interchangeability
This International Standard specifies the requirements for the various elements and dimensions of towing vehicles with rear-mounted coupling and of drawbar trailers, to ensure interchangeability. NOTE Annex B gives examples of different configurations of vehicle combinations; this International Standard deals only with No. B.1.1. This International Standard is applicable to road trains for commercial transport of cargo of the greatest possible variety; it does not cover dedicated or special combinations. Nor does it specify limitations of maximum gross mass and overall dimensions, which are generally laid down by legislative requirements. Vehicles whose couplings form the subject of this International Standard are not interchangeable with vehicles whose couplings are mounted forward and below (which form the subject of ISO 11407 [1]).
Véhicules routiers utilitaires — Accouplement mécanique entre véhicules tracteurs à dispositif d'attelage arrière et remorque à train avant directeur — Interchangeabilité
General Information
- Status
- Published
- Publication Date
- 09-May-2001
- Current Stage
- 9093 - International Standard confirmed
- Start Date
- 24-Feb-2021
- Completion Date
- 13-Dec-2025
Relations
- Effective Date
- 15-Apr-2008
Overview
ISO 11406:2001 specifies dimensional and assembly requirements to ensure interchangeability between towing vehicles with rear-mounted couplings and drawbar trailers. The standard targets commercial road trains designed to carry a wide variety of cargo and addresses the physical interfaces and clearances necessary for safe, repeatable coupling and operation. It does not cover dedicated/special combinations and does not set legal limits for maximum gross mass or overall vehicle dimensions.
Key Topics
- Interchangeability dimensions - Requirements that define how towing vehicles and trailers mate reliably.
- Distance A (drawbar coupling axis to rear end)
- Must not exceed 550 mm.
- Recommended range 420–550 mm when complying with common vehicle-length and loading-length conditions.
- If A exceeds 420 mm, a device enabling coupling actuation at a maximum distance of 420 mm from the outer body is required.
- Front corner radius (dimension C)
- C is the minimum horizontal distance between the drawbar coupling axis and the front corner of the trailer.
- The standard provides a calculation method (clause 2.2) and requires a minimum clearance parameter S ≥ 80 mm to prevent contact under normal operation.
- Annex A gives worked examples (e.g., A = 420 mm, W = 2 500 mm → C ≈ 1 400 mm).
- Heights of towing attachments (H)
- Table 1 sets the required heights for towing attachments on the towing vehicle and the drawbar articulation axis on the trailer, by laden mass bands. Examples include:
- For laden mass ~6–10 t: 700 ±150 mm (towing attachment), 700 ±100 mm (drawbar axis).
- For ~10–14 t: 850 ±150 mm and 850 ±100 mm.
- Above ~14 t: 900 ±150 mm and 900 ±100 mm.
- Table 1 sets the required heights for towing attachments on the towing vehicle and the drawbar articulation axis on the trailer, by laden mass bands. Examples include:
- Scope limits - The standard excludes couplings mounted forward and below (see ISO 11407) and dedicated combinations where contact/damage is expected.
Applications
ISO 11406:2001 is used by:
- Vehicle OEMs and trailer manufacturers to design interoperable coupling systems for commercial fleets.
- Fleet operators and bodybuilders to verify fit and clearance for swap bodies and varying load arrangements.
- Regulatory and conformity assessment teams to check compliance with interchangeability guidance (complementary to legal limits set by national/regional authorities).
Benefits include reduced coupling-related damage, improved fleet flexibility, and predictable fit across different vehicle/trailer combinations.
Related Standards
- ISO 11407 - Couplings mounted forward and below (different interchangeability family).
- Directive 96/53/EC - Maximum authorized dimensions and weights (regional legislative context).
- EN 284 - Swap body dimensions (referenced for loading-length considerations).
For implementation, consult the full ISO 11406:2001 text for the precise clause wording, dimension tables and annex examples before final design or conformity decisions.
Frequently Asked Questions
ISO 11406:2001 is a standard published by the International Organization for Standardization (ISO). Its full title is "Commercial road vehicles - Mechanical coupling between towing vehicles with rear-mounted coupling and drawbar trailers - Interchangeability". This standard covers: This International Standard specifies the requirements for the various elements and dimensions of towing vehicles with rear-mounted coupling and of drawbar trailers, to ensure interchangeability. NOTE Annex B gives examples of different configurations of vehicle combinations; this International Standard deals only with No. B.1.1. This International Standard is applicable to road trains for commercial transport of cargo of the greatest possible variety; it does not cover dedicated or special combinations. Nor does it specify limitations of maximum gross mass and overall dimensions, which are generally laid down by legislative requirements. Vehicles whose couplings form the subject of this International Standard are not interchangeable with vehicles whose couplings are mounted forward and below (which form the subject of ISO 11407 [1]).
This International Standard specifies the requirements for the various elements and dimensions of towing vehicles with rear-mounted coupling and of drawbar trailers, to ensure interchangeability. NOTE Annex B gives examples of different configurations of vehicle combinations; this International Standard deals only with No. B.1.1. This International Standard is applicable to road trains for commercial transport of cargo of the greatest possible variety; it does not cover dedicated or special combinations. Nor does it specify limitations of maximum gross mass and overall dimensions, which are generally laid down by legislative requirements. Vehicles whose couplings form the subject of this International Standard are not interchangeable with vehicles whose couplings are mounted forward and below (which form the subject of ISO 11407 [1]).
ISO 11406:2001 is classified under the following ICS (International Classification for Standards) categories: 43.040.70 - Couplings. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 11406:2001 has the following relationships with other standards: It is inter standard links to ISO 11406:1993. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO 11406:2001 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 11406
Second edition
2001-04-15
Commercial road vehicles — Mechanical
coupling between towing vehicles with
rear-mounted coupling and drawbar
trailers — Interchangeability
Véhicules routiers utilitaires — Accouplement mécanique entre véhicules
tracteurs à dispositif d'attelage arrière et remorque à train avant
directeur — Interchangeabilité
Reference number
©
ISO 2001
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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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 11406 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 11406:1993), which has been technically revised.
Annexes A and B of this International Standard are for information only.
INTERNATIONAL STANDARD ISO 11406:2001(E)
Commercial road vehicles — Mechanical coupling between towing
vehicles with rear-mounted coupling and drawbar trailers —
Interchangeability
1 Scope
This International Standard specifies the requirements for the various elements and dimensions of towing vehicles
with rear-mounted coupling and of drawbar trailers, to ensure interchangeability.
NOTE Annex B gives examples of different configurations of vehicle combinations; this International Standard deals only
with No. B.1.1.
This International Standard is applicable to road trains for commercial transport of cargo of the greatest possible
variety; it does not cover dedicated or special combinations. Nor does it specify limitations of maximum gross mass
and overall dimensions, which are generally laid down by legislative requirements.
Vehicles whose couplings form the subject of this International Standard are not interchangeable with vehicles
[1]
whose couplings are mounted forward and below (which form the subject of ISO 11407 ).
2 Interchangeability dimensions
2.1 Distance between drawbar coupling axis and rear end of towing vehicle
The distance between drawbar coupling axis and rear
...
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