HVS Update 6-2019

Introduction of the steer axle mass declaration 2018

Heavy Vehicle Services wishes to make the transport industry aware of the release of the Steer Axle Mass Declaration 2018, which has been developed as a result of numerous requests from the transport industry. This replaces the 7.0 Tonne Steer Axle Declaration 2016.

The new declaration provides an increase to the allowable twin steer axle group mass limit from 11.0 tonnes to 12.0 tonnes, provided:

  • The vehicle has a Gross Vehicle Mass (GVM) of 22.5 tonnes or more;
  • The axle group is fitted with load sharing suspension;
  • The axle group is fitted with tyres with a minimum width of 375mm; and
  • The vehicle is suitably rated to carry the additional load without any modifications, unless the CEO of Transport has approved the modifications.

The inclusion of twin steer axle groups in the new declaration recognises that both single and twin steer heavy vehicles have similar operational requirements, such as requiring larger engine capacity, additional safety equipment, sleeper cabs and long-range fuel tanks.

As such, the new declaration continues to provide the same increase to the allowable mass limits for single steer axle groups, as the previous declaration.

A single steer axle group on a suitably rated heavy vehicle may exceed 6.0 tonnes when the tyres fitted have a minimum width, as outlined below:
  • 6.5 tonnes provided the tyres fitted have a minimum width of 295mm; or
  • 7.0 tonnes provided the tyres fitted have a minimum width of 375mm.

Whilst the declaration applies to all of the specified heavy vehicles, operators may request that the increased steer axle mass limit be reflected on their permits, provided the vehicle meets the requirements of the declaration. To do this, operators are required to complete either the Application to List or Update Vehicle Information form or the Application to Update Steer Mass Details form, to update the details for each vehicle. These forms can be found on the Forms page of our website

Operators should familiarise themselves with all the requirements stipulated in the declaration, which can be found on the Orders (Notices) page of our website.

For further information, please contact the Heavy Vehicle Services Helpdesk on 138 486 or hvs@mainroads.wa.gov.au


Heavy Vehicle Services

13 March 2019

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The Government of Western Australia acknowledges the traditional custodians throughout Western Australia and their continuing connection to the land, waters and community. We pay our respects to all members of the Aboriginal communities and their cultures; and to Elders both past and present.

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