Most states and territories don’t have specific references to trailer speeds in their regulations therefore for combinations under 4.5 tonnes the maximum permitted speed will be the posted limit. However Western Australia is slightly different in that it also specifies the posted limit, but for trailers with an Aggregate Trailer Mass of 750kg or greater, the maximum towing speed is limited to 100km/h.
There are a couple of other points to consider however. One is that you have an obligation to always tow at a safe speed, which depending on the combination and conditions, may be lower than the posted speed limit. Also some vehicle manufacturers specify a lower maximum speed when the trailer mass exceeds a certain level. Ultimately, it will be up to you to determine what is a safe and appropriate towing speed having regard to state law, the vehicle manufacturer’s specifications, the road conditions and vehicle stability and safety.
Remember that when towing, your vehicle is heavier and will be harder to start off, accelerate and stop, so you will need to drive accordingly.
Mandatory towing equipment
There is certain equipment that is mandatory for towing any trailer. This includes obvious things like tow bars and trailer wiring connectors. However, particularly where the trailer mass is approaching the upper limit of the vehicle’s specifications, its manufacturer may mandate certain additional equipment. Load levelling devices, high capacity tow bars, heavy-duty rear suspension and brake controllers are examples. Where specified, this equipment must be fitted.
Load distribution / levelling devices
Load distribution devices are used to return the tow vehicle’s attitude to as near level as possible once the trailer has been connected. They do this by transferring some of the weight imposed on the tow vehicle’s rear axle to the front axle, which amongst other things, benefits steering control and braking. They are available in a range of sizes and styles to suit the particular application.
However the vehicle and towbar must be strong enough to withstand the increased loads imposed by such systems. If the tow bar does not have provision for, or was not originally intended to have a load distribution device fitted, the advice of the towbar manufacturer should be sought before fitting one.
Some vehicle manufacturers specify load-levelling devices as a mandatory part of their towing package, however some specifically advise against their use due to towbar and vehicle design issues.
Load distribution systems are not intended to compensate for excessive ball or rear axle loads or to correct poor trailer loading.
Other levelling devices include height adjustable shock absorbers and original equipment self-levelling suspension systems. Before attempting to tow heavy loads with self-levelling suspension systems, or using weight distribution devices with them, the advice of the vehicle’s manufacturer should be sought.
About tow bars
Just because the car you bought came with a tow bar don’t automatically assume that it is suitable for a caravan or other heavy trailer. Many tow bars are only intended to tow light trailers and will be totally unsuitable for heavy use.
Tow bars are available from a number of sources, but most commonly they are purchased from a specialist tow bar manufacturer or as original equipment from the vehicle manufacturer’s spare parts and accessories outlet.
When buying a tow bar there may appear to be a price benefit in buying non-genuine, but keep in mind that the vehicle manufacturer’s towing package is often more than just a tow bar. Such packages can often include things like body reinforcement, heavy-duty suspension and additional transmission oil coolers, all of which are designed to maximise safety and vehicle durability.
Another point often overlooked is the height of the vehicle’s tow bar in relation to the trailer’s draw bar. For best results the trailer should be slightly “nose down”. If it tows “nose up", it may be unstable. Usually problems such as this can be corrected but it is work best left to a specialist in the field.
If the tow bar tongue or ball obscures the rear number plate, it must be removed from the tow bar when not in use. For further information about tow bars see our Trailer and Tow vehicle specifications explained fact sheet.
Fifth wheel trailers
Fifth wheel caravans and horse floats are becoming increasingly popular due to their larger size and carrying capacity. They are designed to be towed by trucks and utilities that have the towing connection in the vehicle’s tray rather than at the back like a conventional tow bar. The regulations covering fifth wheel trailers are quite different to those for a conventional trailer and we therefore recommend that you seek advice from the manufacturer if you are considering the purchase of this type of trailer.
All States and Territories require the use of safety chains. Safety chains must be strong enough to hold the trailer should the trailer coupling accidentally disconnect, and comply with the appropriate Australian Standard. Trailers up to 2500 kg ATM are required to have one safety chain while trailers from 2,500kg to 3,500kg must be fitted with two safety chains. The “D” shackle used to connect the safety chain to the vehicle’s tow bar must have a load rating equivalent to that of the safety chain.
- Trailers up to and including 750kg GTM do not require brakes*
- Trailers not over 2,000kg GTM must have brakes that operate on at least one axle
- Override brakes are acceptable on trailers up to and including 2,000kg GTM
- Trailers over 2,000kg GTM are required to have brakes that apply automatically if the trailer becomes detached from the towing vehicle
- Trailers over 2,000kg GTM must have brakes on all wheels
- Brakes other than override systems must be able to be operated from the driver’s seat
The cost and complexity of trailer brake systems will vary depending on the application, however where required, most light trailers will have either override or electric brakes. Electric brakes require the installation of a control unit in the tow vehicle.
* Note also that some vehicles have a low un-braked trailer weight limit and will therefore require brakes to be fitted to trailers that have GTM of less than 750kg.
Extended towing mirrors
Extended towing mirrors are required where the vehicle’s existing mirrors cannot provide a clear view past the caravan or trailer.