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Maintaining Your Vehicle & Trailer

Regular maintenance of your vehicle and trailer is essential for safe towing. Have them checked regularly to ensure they are in a safe and roadworthy condition.

The trailer’s wheel bearings, suspension and brakes must all be in good working order and tyres must be properly inflated.

Storing Your Trailer

It’s a good idea to take some of the mass off your trailer’s springs and tyres if it’s going to be stationary for an extended period of time. The best way to do this is by placing blocks under the chassis behind the wheels and under the point where the A-frame attaches to the chassis. By using a proper approved jack to raise and lower the trailer, this can be achieved quite easily.


Gas cylinders and LPG regulators should also be checked regularly by a qualified technician. For example, if left out in the open, your regulator may have been affected by water. If this is the case, it needs to be drained and cleaned thoroughly to prevent corrosion, which may prevent it from working properly. Check that all hoses and pipes are securely connected and also check the date stamp on your cylinders, which must be checked for continued service life once every 10 years at a certified gas cylinder testing station. It is illegal to fill cylinders which are past their due test date.

Checks Before the Trip

  • Check oil, water, brake fluid, and battery.
  • Inspect all tyres carefully. If your trailer has not been used for a long time, the tyres may be soft. And remember, when towing heavily loaded trailers your vehicle’s tyre pressures should be increased to the level recommended in the owner’s handbook or on the tyre placard. If in doubt, contact your local tyre dealer.
  • Check that your vehicle and trailer’s wheel nuts have been tightened to the manufacturer’s specifications. To tighten the nuts, use a torque wrench to the torque recommended by the manufacturer (usually around 90ft lb or 125Nm). Wheel nuts should then be re-tightened after each 100kms for the first 400kms and checked every 1,000kms, at six month intervals thereafter or after having your caravan serviced.
  • Ensure the coupling socket and ball match in size.
  • Check that the coupling is correctly and securely fastened.
  • Check that the safety chains are correctly connected.
  • Check to ensure that the trailer brake and light connections are secure and that all lights work.
  • Check that the towing lights, number plates and registration labels of your caravan are clearly visible.
  • Disengage any reversing catch fitted to the trailer coupling (as used with over-ride brakes).
  • Make one or two test stops to check that the brakes are working properly.
  • Ensure that your load is properly secured.
  • Limit the amount of load in the boot of the tow vehicle.
  • Ensure that the rear vision mirrors on the tow vehicle are properly adjusted.
  • Ensure that the gas cylinders are properly secured.
  • Ensure that the gas cylinders are turned off while travelling and that the refrigerator door is locked.
  • Check that the roll-out awning is stored away and locked in the travel position.
  • Remove the jockey wheel from its clamp and store it in the boot of the car or RV. Or if it is of the swivel mount variety, lock it in the travelling position.
  • Check that the front and rear corner stabilisers are in the up position.
  • Ensure that the hand brake of the trailer has been correctly released.
  • Check that the roof hatches, windows, doors and stone shields are secure.
  • Check that the electrical cord has been disconnected and stored away.
  • Check that the TV antenna is in the travel position.

Checks During the Trip

  • Check that the couplings and chains are still securely fastened.
  • Check that the brakes and wheel bearings are not overheating, by comparing to your car brakes.
  • Check that light connections are still secure and that all lights are working.
  • Check that the tyres are still sufficiently inflated.
  • Check that the load is still secure.
  • Check that the roll-out awning is properly locked in the travel position.

Towing Your Caravan

The loaded mass of your trailer must not exceed:

  • the capacity of the towbar; or
  • the maximum towing mass specified by the tow vehicle’s manufacturer; or
  • the maximum ball weight specified by the tow vehicle’s manufacturer.

The Driver

Apart from adding to the driver’s legal responsibilities, towing requires a greater degree of knowledge and skill than normal driving. When towing, you should:

  • Allow for the extra length and width of the trailer when entering traffic.
  • Apply the accelerator, brakes and steering smoothly and gently to avoid sway, especially in wet or slippery conditions.
  • Maintain a space of at least 60 metres between you and the vehicle in front to allow for a longer stopping distance.
  • Engage a lower gear in both manual and automatic vehicles to increase vehicle control and reduce brake strain when travelling downhill.
  • Allow more time and a greater distance in which to overtake. When towing, your vehicle’s capacity to accelerate is reduced.
  • If possible, reverse with a person watching the rear of the trailer.
  • Where areas are provided, pull off the road to allow traffic building up behind you to overtake.
  • Be aware that towing is more stressful than normal driving and is more likely to cause fatigue. Therefore, more rest stops should be planned.

Caravan Sway

If your caravan begins to sway or snake, remain calm and avoid the urge to apply the towing vehicle’s brakes. Don’t try to steer out of the swaying / snaking. Alternatively hold the vehicle steady and try to stay in the lane. Gently apply the caravan’s electric brakes using the manual control in the tow vehicle. Otherwise, where conditions permit, continue at a steady speed or accelerate slightly until the sway stops.

When a condition of sway has been corrected, slow down and pull off the road safely. Check that your load is correctly distributed within the trailer, making sure that heavier items are placed over the axles of the caravan. A caravan that doesn’t have the load distributed correctly may not handle well and may be the cause of swaying / snaking.

Loading Trailers

It is important not to overload your trailer. You should not exceed the maximum load specified or recommended by the trailer manufacturer, nor should you exceed the tyre or coupling capacity. Trailers now have attached to their drawbar or body a plate displaying the ATM, which is the maximum allowable weight.

For safety and ease of towing, the ball mass (the mass towards the front of the trailer carried by the tow ball of the towing vehicle) should be about 10% of the total laden trailer weight. The ball mass can be measured either at a weighbridge by resting only the jockey wheel on the scale, or by placing a ball mass scale under the coupling then taking the weight off the jockey wheel. Depending on capacity, bathroom scales can also be used.

Weight Distribution Hitches

The trailer’s drawbar should preferably be level when being towed. Towing applies a downward force on the rear of your vehicle which is referred to as ‘ball weight’. This weight will be carried by the rear suspension, which can cause the back of the tow vehicle to sag. In response, the front of the vehicle will rise and the steering will feel light, due to the lower weight on the front wheels. This can cause loss of steering and braking performance (increased wear and tear on the rear suspension and tyres will also result).

Weight distribution hitches will help return your vehicle close to the original dynamics by re-distributing the effects of this ball weight to the original balance between front and rear suspensions, thus levelling out the vehicle/trailer combination.

Some vehicle manufacturers require the use of a Weight Distribution Hitch to be able to tow to their stated maximum capacity. In this situation you are legally obliged to use them. However, some vehicle manufacturers prohibit their use, so you will need to check your towing vehicle’s manual.

Remember, Weight Distribution Hitches are not a means of lowering the ball weight, and you still cannot tow more than the maximum ball weight as set out by the vehicle/towbar manufacturer. You should always consult your vehicle owner’s manual for the true towing capacity of your vehicle and match that with the correct towbar.

Fitting of weight distributing hitches is not recommended with over-ride brakes, as the hitch interferes with the application and release of the brakes, and may cause brake malfunction. Neither should they be used in extreme off road conditions.

Sway Control

When the weight of a loaded caravan or trailer is transferred via the tow-ball connection to the tow vehicle suspension, a Weight Distribution Hitch matched to the tow-ball weight is the first essential for sway control. This restores the tow vehicle front wheel traction and tow vehicle stability.

External factors such as cross winds and overtaking trucks and buses create significant side thrust forces that increase in intensity with increasing caravan/trailer size and load. If these forces are noticeable after fitting an appropriate Weight Distribution Hitch, an added sway control unit should be fitted.

Speed Limits

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.

When the motor vehicle and trailer combination (GCM) exceeds 4.5 tonnes, vehicle users should consult with the appropriate state or territory transport authority regarding speed limits. A safe speed, satisfactory stopping distance and any other requirement imposed by the manufacturer of the towing vehicle also apply.

For certain road conditions (e.g. sharp bends, steep descent, winding roads), special speed limit signs may be posted for trucks, roadtrains and buses. You must not drive at a speed greater than the speed shown on the sign.

If the posted speed-limit is over 100km/h and the RV or vehicle and trailer have a GCM over 5 tonnes, or any other vehicle with a GVM over 12 tonnes, the speed-limit applying to the driver for the length of road is 100 kilometres per hour. (Australian Road Rules – February 2009 version)

Maximum Trailer Mass

Throughout Australia, the allowable maximum mass for the trailer is either the capacity of the tow vehicle’s towing attachment or the towing limit specified by the vehicle manufacturer for the towing vehicle, whichever is the least.


If the vehicle’s manufacturer has not made a recommendation as to the towing mass, then the following rules apply:

A vehicle may tow a laden trailer of up to one and a half times the unladen mass of the tow vehicle, provided that the towbar is rated accordingly and the trailer is fitted with brakes that comply with the requirements stipulated in the Australian Design Rule ADR38.

If the trailer is not fitted with brakes, then the maximum mass must not exceed the unladen mass of the motor vehicle. The unladen mass of the vehicle can be found in the vehicle’s handbook, or check with your dealer.

All trailers with a GTM exceeding 750kgs must have their own brakes.