australian national towing
In December, 1998, agreement was reached by all State’s Ministers of Transport
to implement national towing regulations. In essence, the national rules state
that “A motor vehicle with a Gross Vehicle Mass (G.M.V.) not exceeding 4.5 tonnes must not, without the approval of an authority, tow a trailer with a
mass (including any load) exceeding;
The capacity of the towing apparatus fitted to the
vehicle, or A relevant maximum trailer mass specified by the
Put simply, the most you can tow is the amount specified by the vehicle
manufacturer or the capacity of the towbar - WHICH EVER IS LEAST.
If you want to know how much your vehicle can tow, firstly check the owners
manual or vehicle sales brochure for the manufacturer’s towing recommendations.
Secondly make sure that the towing capacity is as least as much, if not more,
than the mass of the trailer, including its load. If you are unsure how strong
the towbar is, have a chat to a reputable towing equipment specialist.
In the case where a motor vehicle manufacturer has not
specified a maximum towing mass, the limit is stated to be:
1.5 times the unladen or kerb mass of the motor vehicle if the trailer is fitted with brakes;
mass of the motor vehicle if the trailer is not fitted with brakes.
It should be noted, however, that the above will rarely apply as apart from
using a truck, just about every vehicle that is likely to be used for towing a
caravan, boat trailer, horsefloat or similar has a manufacturer’s towing
Owners of 4WDs and light commercial vehicles should also be careful that they do
not exceed the Gross Combined Mass (G.C.M.) of the vehicle. The GCM refers to
the maximum vehicle plus its load, including a trailer, is permitted to weigh.
It is possible that when a motor vehicle is loaded with, for example, five
adults, their luggage and camping gear that the maximum allowable trailer mass
has to be reduced so as to not exceed the GCM.
While this may sound a little confusing, it is important that this is considered
so as to not void the warranty or insurance.
For a motor vehicle and trailer combination that has a GCM of
less than 4.5 tonnes, the posted speed limits apply - unless the manufacturer of
the towing vehicle has stipulated a lower towing speed limit.
While the maximum speed limit in Western Australia is 110
km/h, the maximum for a vehicle towing a trailer, caravan or other vehicle is
You should remember that in some cases motor vehicle manufacturers place speed
restrictions on a vehicle when towing over a certain mass. Ford only permits
100km/h if the load is less than 1200 kg. At 1600 kg this drops to 90km/h. The
speed further reduces until at 2300 kg, 80km/h is the maximum. Holden takes a
similar approach but also ties the vehicle speed to the type of towing equipment
fitted. Spending a few minutes reading the trailer towing section in the owners
manual is highly recommended.
In 1989 Australian Design Rules (ADRs) were introduced which affect the
construction and towing of trailers, including caravans. Currently there are no
towing regulations which specifically refer to ‘caravans’. The ADRs include the
requirement for plates on trailer drawbars which amongst other information
states the aggregate, or maximum, mass of the trailer and data on the towbar
which indicates the rating of that towbar. It should be noted that ADR 62 states
that the rated capacity of the towbar …. “shall not exceed the vehicle
manufacturer’s recommendations”. Below is a summary of the rules relating to
towing weights which should assist in the selection of towing equipment and/or
caravan and the towing speeds applicable to various states.
While there are some variations in the Road Traffic Regulations in different
States, most agree on the following safety aspects:
The trailer must not be bigger or heavier than the driver can safely control,
The total or laden mass of the trailer must not be more than:
- the maximum mass (A.T.M.) determined by the trailer manufacturer and as stated
on the trailer plate,
- the load rating of the trailer’s coupling of the towbar fitted to the towing
- the total load rating of all the trailer’s tyres.
The combination of tow vehicle and trailer must be “properly set up”. This means
that there is a load of about 10% of the total trailer mass on the towbar and
that the outfit has a level attitude. Generally this necessitates the use of a
load distributing device.
Exceeding the maximum towing load as recommended by the towing vehicle
* Nulify insurance, and
long term vehicle safety and reliability.
The new towing regulations allow the owner of a 4WD, ute
or car to tow a trailer weighing up to the vehicle maker's
Unbraked trailers with an all-up weight under 750kg are approved under the new
uniform law, but trailers weighing more then 750 kg must be fitted with brakes.
The changes are a result of uniform vehicle standards proposed by the National
Road Transport Commission and approved by Federal Parliament.
A FEW DEFINITIONS
ATM (Aggregate Trailer Mass)
The total laden weight of a trailer, which includes the tow ball
mass and whatever you add as payload (eg. water, gas, luggage). The ATM
is specified by the trailer manufacturer and must not be exceeded.
GCM (Gross Combination Mass)
The maximum laden mass of a motor vehicle plus the maximum laden
weight of any trailer it can tow. The GCM is specified by the vehicle
GTM (Gross Trailer Mass)
The total permissible mass which includes whatever you add as
payload (eg. water, gas and luggage) that can be supported by the wheels
of a trailer. This does not include the mass supported by the tow ball.
The GTM is specified by the manufacturer and must not be exceeded.
GVM (Gross Vehicle Mass)
is the maximum allowable total mass of a fully loaded motor vehicle,
consisting of the tare mass (mass of the vehicle) plus the payload
(including passengers, accessories & the tow ball mass).
The unladen weight of the trailer.
Tow Ball Mass
The weight imposed on the rear of the tow vehicle's tow ball from
the coupling of a trailer or caravan.
Payload is specified by the manufacturer. It must not be exceeded
under any circumstances. Safety, insurance & warranty may be affected if
the specified payload is exceeded.
info by Rob