Simple trailers

A simple trailer is a trailer that has one axle set, and is not a semi–trailer. A simple trailer is, therefore, attached to the towing vehicle at a position well behind the position specified for a semi-trailer. Stinger Steer Transporters are simple trailer combination vehicles. The gross mass of a simple trailer (including its load) is the mass transferred to the ground through the axle(s) of that trailer. Any transferred weight from a following trailer must be included in the calculation of gross mass of the first trailer. The gross mass of a combined rigid vehicle and one simple trailer must not exceed 36 tonnes (except may be 40,000kg if it has an HPMV permit and an approved towing connection – see section 4.3(9) of the Rule).

A heavy simple trailer must have an axle set consisting of either:

• a single axle set, or

• a tandem axle set, or

• a tri-axle set.

The maximum overall length for a simple trailer (including drawbar and load) is 12.5 metres. The maximum overall length for a rigid vehicle and simple trailer combination (including load, but excluding collapsible mirrors) is 22 metres.

For a simple trailer, forward distance means the distance from the rear axis to the centre of the point of attachment of the towing vehicle. The maximum is 8.5 metres.

Rear overhang means the distance from the rear axis to the rear of the vehicle or its load, whichever is greater. The maximum rear overhang for a heavy simple trailer is four metres or 50 percent of the forward distance, whichever is less.

For a light simple trailer, the maximum rear overhang is four metres.

For simple trailers, front overhang means the distance from the centre of the tow coupling to the foremost point of the vehicle (including its load). The maximum is 2.04 metres radius arc ahead of the tow coupling.

For a rigid vehicle towing a heavy simple trailer the tow coupling position must be at least 700 millimetres behind the rear axis of the rigid vehicle and not more than a distance equal to 50 percent of the wheelbase of that vehicle. The wheelbase is measured from the rear axis of the rigid vehicle to the foremost axle of that vehicle.

For simple trailers, inter-vehicle spacing means the distance between the towing vehicle (excluding the tow coupling shroud) and the trailer (excluding the drawbar but including the load). The maximum is four metres. There is no minimum spacing for simple trailers. The trailer (or its load) may overhang the towing vehicle.