Towing Guide

It’s no secret that trucks available from Performax are towing champions – designed, built and ready to tow loads that leave conventional Australian utes struggling.

Tow Haul Mode

Not only do Performax trucks have the torque, power and suspension to make easy work of the biggest of towing challenges, but they have onboard technology specifically tailored to making the job of “hauling” (as it’s called in the States) so much easier. Features like tow/haul mode, trailer brake controllers, hill start assist and available exhaust brakes all contribute.

Our vehicles tow big loads, and do so with little wear-and-tear to the vehicle itself because that is what they are built to do.

Whether it be towing a caravan, boat trailer, fifth wheel caravan, horse float or gooseneck, Performax trucks will exceed your expectations, however, owners need to be aware of the legal and safety limits that need to be observed and followed.

To ensure you are towing legally and safely, there are three measurements that you need to understand – GVM, payload and GCM.


GVM 1 for web

GVM for a truck towing a caravan includes tow ball weight, but not the weight of the caravan.

GVM 2 for web

GVM for a truck towing a fifth wheeler includes the pin weight, but not the weight of the fifth wheeler.


The gross vehicle mass (GVM) or gross vehicle weight rating (GVWR) is the maximum operating weight of a vehicle as specified by the manufacturer including the vehicle’s chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo.

The GVM is shown on the compliance plate of the vehicle itself, which is usually placed on the centre pillar between the two passenger-side doors.Exhaust brakes

Although excluding the weight of any trailers, the GVM includes the pin-weight of any gooseneck or fifth wheel caravan or the ball weight of a trailer that is resting on the tow vehicle.

Because stopping a load is as important as pulling it, It is possible to increase a vehicle’s GCM by fitting air brakes. Please ask your Performax salesperson for details.

GVM and licensing

In Australia, a car driver licence is limited to driving vehicles up to a maximum GVM of 4495 kg (9900 lb). Beyond this, a different class of licence is required. A vehicle with a GVM under 4495 kg is termed a light vehicle, while those over 4495 kg are termed heavy vehicles.

Many models of truck, for example F-Trucks, Silverado or GMC Sierra Denali, are manufactured to have a GVM rating of 5000 to 7000 kg (11,000 to 15,400 lb) but sold with the option of a GVM of just under 4495 kg so that they can be driven on a car licence. This is called a GVM downgrade.

As a government-approved provider, Performax International and its dealers may be able to assist with GVM downgrades on some vehicles to allow driving on a car licence. This is covered under state legislation, therefore differs from state-to-state.


The payload is the maximum permissible weight that a vehicle is able to carry. This usually includes fuel, passengers and any load.

The payload is the difference between the GVM and Tare Weight.

Tare weight, sometimes called unladen weight, is the weight of an empty vehicle – no oil, no petrol or anything else (the tare weight of each individual truck sold by Performax is shown on the compliance plate).

For example, a truck may have a GVM of 4536 kg and a tare of 3487 kg. Therefore the payload is 4536 kg – 3487 kg = 1049 kg.

GCM (gross combination mass)

GCM 3 for web

GCM - to determine visit your local weigh bridge with you fully laden vehicle and trailer

The gross combination mass rating (also Gross Combination Weight and maximum authorised mass), which can be abbreviated to GCM, MAM, GCWR is the maximum allowable combined mass of a towing road vehicle, passengers and cargo in the tow vehicle, plus the mass of the trailer and cargo in the trailer. This rating is set by the vehicle manufacturer.

The quickest way to determine if you are within your GCM is to visit a weighbridge after you are fully laden for a trip.

Are you safe and legal?

So when it comes to working out if your Performax truck and your trailer – whether it be a gooseneck, caravan of fifth-wheeler – are legal and safe, you need to ensure that your vehicle’s payload, GVM and GCM are all within the legal limits.

If your vehicle and trailer are over any of the required limits for payload, GVM or GCM, then you are illegally towing.

GCM and licensing

You can tow with a GCM of up to nine tonne with a car licence, but anything over this will require a Light Rigid licence.


How can I determine the rating or capacity of my vehicle?

If your vehicle has a tow rating this can be found in the handbook under the towing section. The vehicle tow rating will include a trailer weight capacity and a trailer ball weight capacity.

When do I need to install air brakes?

An air brake kit will need to be installed on your truck to operate the airbrakes on your trailer/caravan/fifth-wheel/gooseneck when the trailer exceeds 4.5 tonne.

How can I check my ball weight?

Ball weight refers to the weight on the front end of the trailer not carried over the axles. As a rule you should aim to have 10 percent of the total trailer weight as ball weight. This can be measured at a weigh bridge by resting the jockey wheel only on the scale.

What towball should I use?

The Australian Standard AS4177-2 recommends that 50mm tow balls with a rating of 3500kg be used for towing trailers up to 3.5 tonne. The capacity should be stamped on the ball plus the manufacturer's identification and a '50' to indicate the tow ball diameter in millimetres.

When should a brake control unit be fitted?

All trailers with an aggregate trailer mass (including the load) over 750kg must be fitted with brakes to comply with national road regulations. Any trailer with electric brakes needs a brake controller to activate the operation of the brakes. The brake controller sets the timing and level of power output to the trailer brakes when activated by pressing the brake pedal in the vehicle.

What are the regulations relating to towing in different States of Australia?

A set of national towing regulations are now in place governing towing in Australia for trailers up to 3500Kg aggregate of loaded trailer mass. In short the loaded trailer must not exceed the recommended towing capacity of the vehicle.

For more information about towing, ask your local Performax dealer.