12 Towing connections
Reasons for rejection
1. A drawbeam fitted to a heavy vehicle, other than a tractor to which section 12-4 applies or a recovery service vehicle, does not have evidence of certification to NZS 5446, ie
a) the drawbeam was fitted before the last CoF inspection, and after 1 January 1997, and no LANDATA record has been entered,
Note Before 1 January 1997 certification was required but for inspection purposes the LANDATA record need not be checked
b) the drawbeam was fitted after the last CoF inspection and
i. a valid LT400 form has not been presented, or
ii. the HVS certifier was not of category HVET or HMTD, or
c) there is no valid certification label or plate attached to the vehicle as required in Table 12-3-1.
2. The certification label or plate:
a) is not indelible, or
b) is illegible, or
c) is not complete, or
d) is not attached to the drawbeam in an easily visible position, or
e) does not match the vehicle, or
f) has obvious signs of tampering, or
g) has expired.
3. A hook- or pin-type coupling does not have a locking device or a separate means of retaining this device in the locked position.
Condition and performance
4. A towing connection component is:
a) damaged, deformed, cracked or has significantly deteriorated, or
b) worn beyond manufacturer’s specifications, or
c) not securely attached, or
d) missing, or
e) not mounted in accordance with manufacturer’s specifications.
5. The towing pin diameter is worn to less than (Note 1):
a) 36.4mm for a 40mm pin, or
b) 46.4mm for a 50mm pin.
6. A towing hook, pin or ball has been repaired or welded.
7. Towing connection components fitted to a vehicle must ensure that a secure connection can be maintained between the towing and towed vehicles under all conditions of loading and operation for which the vehicle was constructed.
8. A drawbeam is sliding or adjustable.
9. Locking of the coupling is not readily verifiable by visual inspection.
10. A coupling locking device is in such condition that it is not effective.
11. A drawbeam fitted to a heavy vehicle was last certified by Peter Wastney (PW) of Peter Wastney Engineering Ltd (for sample plates see Figure 12-3-2).
12. A drawbeam fitted to a heavy vehicle was last certified by Patrick Chu (ZC) of Transport and Structure Ltd (for sample plates see Figure 12-3-2).
Modification and repair (Note 4)
11. A modification or repair affects the drawbeam and:
a) the modification is not for the purpose of law enforcement or the provision of emergency services, or
b) is missing proof of HVS certification, ie:
i. the vehicle was modified or repaired before the last CoF inspection, and after 1 January 1997, and no LANDATA record has been entered,
Note Before 1 January 1997 certification was required but for inspection purposes the LANDATA record
need not be checked
ii. the vehicle was modified or repaired since the last CoF inspection and no valid LT400 form from a HVS Certifier of category HVET or HMTD has been presented.
Manufacturer’s wear limits may be used instead of those stated.
Note 2 Definitions
Coupling means that part of a vehicle that is specifically designed to enable it to be connected to another vehicle; it does not include a structural member of the towing or towed vehicle (eg fifth wheel, hook, pin, ball or socket type).
Drawbeam means that part of the towing vehicle to which a coupling is fitted to enable a heavy trailer to be connected; it includes the attached coupling.
Full trailer means a trailer with two axle sets, the foremost of which is steered by a drawbar; includes a semi-trailer with non-steering axles coupled to a converter dolly.
Some special-use vehicles, such as fertiliser trucks and trailers, are fitted with towing connections where the towing eye is fitted to the towing vehicle and the pin- or hook-type coupling to the trailer. This is permitted. In these cases, please refer to heavy trailer pages of section 8-3 for wear limits and other relevant requirements.
A towing connection that was certified to New Zealand standard 5446: 1987 (superseded) before November 2007 may continue to comply with and be certified to that standard until the towing connection is modified.
Table 12-3-1. Minimum information on drawbeam certification label/plate
NZS 5446: 1987
NZS 5446: 2007
Company or agency name
Maximum towed mass (kg)
Expiry date (if certified on or after 1 August 1991)
Person, company or agency name
Maximum towed mass
Permitted static vertical load (where applicable)**
Coupling D value (minimum) (where applicable)**
*Prior to 1 December 2016 the engineer's job file number could have been used instead of the LT400 number.
**If these values are not applicable, ‘N/A’ must be used (from 1 October 2020). Prior to 1 October 2020 the plate may have a blank space or a zero, nil or N/A value.
- hinged drawbars do not have a vertical load rating
- most pintle hooks/eyes do not have a D value.
Figure 12-3-1. Drawbeam components
Reproduced from Figure 3 of NZS 5446: 2007 with the permission of Standards New Zealand under Licence 000711
Figure 12-3-2. Sample certification plates (Peter Wastney Ltd and Patrick Chu (ZC) of Transport and Structure Ltd)
|Peter Wastney Ltd|
|Patrick Chu (ZC) of Transport and Structure Ltd|
Summary of legislation
- Land Transport Rule: Vehicle Dimensions and Mass 2002
- Land Transport Rule: Heavy Vehicles 2004
- New Zealand Standard 5446: 1987, Code of Practice for Heavy Motor Vehicle Towing Connections: Drawbar Trailers
- New Zealand Standard 5446: 2007, Heavy Vehicle Towing Connections – Drawbeams and Drawbars.
1. A drawbeam fitted to a vehicle used in a combination, (other than a tractor to which section 12-4 applies or a recovery service vehicle) must comply and be certified to NZS 5446.
2. A hook- or pin-type coupling must have an effective locking device and a separate means of retaining this device in the locked position.
Condition and performance
3. Towing connection components fitted to a vehicle must ensure that a secure connection can be maintained between the towing and towed vehicles under all conditions of loading and operation for which the vehicle was constructed.
4. A drawbeam used for towing a full trailer must not be sliding or adjustable.
5. Locking of the coupling must be readily verifiable by visual inspection.
Modification and repair
6. A modification or repair that affects the drawbeam must be inspected and certified by an HVS certifier of category HVET or HMTD.
Page amended 1 October 2020 (see amendment details).
- General vehicles
- Heavy vehicles
- 1 Vehicle identification
- 2 Vehicle exterior
- 3 Vehicle structure
- 4 Lighting
- 5 Vision
- 6 Entrance and exit
- 7 Vehicle interior
- 8 Brakes
- 9 Steering and suspension
- 10 Tyres, wheels and hubs
- 11 Exhaust
- 12 Towing connections
- 13 Miscellaneous items
- 14 Load restraints
- 15 Certificate of loading
- 16 Transport service licence
- Light PSVs
- Heavy PSVs
- General trailers
- Heavy trailers
- Unclassified vehicles
- Technical bulletins (general)
- Technical bulletins (CoF)
- Interim amendments