Towing regulations And recommendations

For the moment all trailer and towing and DIY will go here
To See All The SubForums Pls Register Or Sign On

Towing regulations And recommendations

Postby kfxnando » Sun Jan 23, 2011 4:50 pm

very difficult to get info on local regulations!!

however info on UK and Aus is readily available!!

and here is some!!

The coupling must be strong enough to take the weight of a fully loaded trailer. There are five main parts involved in a trailer coupling: the towbar, the ball mount or tongue and the tow ball are all attached to the tow vehicle, while the coupling body and the trailer draw bar or 'A' Frame form the attachment points on the trailer.
The Towbar


very similar to the set up on the Jeep

The Towbar:
The towbar is the framework attached to the back of the tow vehicle. For safe towing, a properly designed and fitted towbar with
an adequate certified weight rating is mandatory. Further, the load capacity of the towbar and the trailer coupling must be equal to or exceed the loaded mass of the trailer.

If you bought a second hand vehicle with a towbar already attached, be especially careful. You need to make sure that the towbar is appropriate for whatever you intend towing. For example, although ideal for the previous owner's box trailer, the towbar might be totally unsuitable for your caravan.

Note: Towbars should not protrude dangerously when your trailer is not connected.

Unless a permanent part of the vehicle, it is compulsory for all towbars manufactured after 1 July 1988 to clearly and permanently display the maximum load rated capacity plus the make and model of vehicle for which they are intended, or alternatively, the manufacturer's name, trade mark and part number. Check for this information to help you ascertain whether the towbar suits your needs.
ball mount and tongue
The Ball Mount or Tongue

The Ball Mount or Tongue:
The ball mount, also known as the tongue, is the section of the towbar to which the towball is attached. It is usually a flat 75mm wide, 16 to 20mm thick steel bar, which may be either straight or curved to achieve the correct coupling height. If the ball mount or tongue obscures the number plate it must be removed from the towbar when the trailer is not attached.
tow ball

The Tow Ball:
Tow balls suitable for weights of up to 3,500kgs must be 50mm in diameter and should comply with Australian Standard 4177-2. The tow ball must be a one-piece element, the shank of which should be 22.2mm in diameter. The top face of the sphere should be clearly stamped with the capacity (3.5t) and tow ball diameter (50). The tow ball unit must be fitted to the vehicle with a locking washer and an appropriately sized nut. According to the Australian Standard 4177.2 the manufacturer's name or trademark must also be stamped on the flange of the tow ball.


The Coupling Body
The coupling body is the section that is attached to the 'A' frame of the trailer. It forms a socket for the tow ball and provides the necessary pivot point between the trailer and the towing vehicle. Coupling bodies commonly in use can range in capacity from 750kgs to 3,500kgs. They must be marked with their capacity, as well as the manufacturer's name and the size of the tow ball for which they are suitable.

It is important to ensure that the coupling body's capacity exceeds or is at least equal to the fully laden weight of the trailer.
Coupling Height - 50mm Ball Couplings


Coupling Height - 50mm Ball Couplings:
Ball couplings used on trailers with an ATM of up to 3.5 tonnes must comply with Australian Standards and be installed so that the height of the centre of the body of the ball couplings is between 350mm and 460mm from the ground when laden.
A frame drawbar
The Trailer's 'A' Frame (Drawbar)

The Trailer's 'A' Frame (Drawbar):
This is the front section of the trailer or caravan chassis to which the coupling body is attached with bolts, nuts and locking washers. Welding the coupling body is also permitted on trailers under 1000 kgs provided the manufacturer has specified that this approach is suitable and has provided welding instructions, which must be followed.

The "A" frame or drawbar is required under the Australian Design Rules to be of sufficient strength for the specified trailer ATM, and must be able to be proven to do so by engineering calculation. It is therefore not advisable to add to the drawbar additional items that will increase the load on the drawbar, without the specific approval of the trailer and towbar manufacturers. Increasing the downward load on the trailer drawbar will also increase the tow-ball weight on the towbar.

Excessive overloading of towbar ball weight will affect its performance and may void manufacturer’s warranty.
safety chain
Safety Chains


Safety Chains:
Safety chains are compulsory in all States and Territories of Australia. They must be strong enough to hold the trailer and prevent the drawbar from touching the ground, should the coupling fail or be accidently disconnected from the ball.

Trailers less than 2,500kgs ATM must be fitted with at least one safety chain of at least 9.5mm in diameter. Trailers over 2,500kgs ATM and up to 3,500kgs must have two safety chains. Chains must comply with AS4177-4 and have a size designation at least equal to the trailer ATM.

The chains attach the 'A' frame or drawbar of the trailer to the main towbar framework on the vehicle. The attachment must be made with 'D' shackles of equivalent strength to the chains. It is vital that the chains are attached to the main towbar framework and not to a detachable ball mount or tongue. Safety chains must be stamped with the chain's capacity, the manufacturer's identification and the digits 4177.

The chains should be as short as possible, leaving only enough slack to permit tight turns. If two are required they should be crisscrossed under the trailer tongue to prevent the forward end of the drawbar from hitting the ground if the coupling becomes disconnected.

although our government does not always do what should be done!!
so we cant even say we should be similar!!

more to follow!!
User avatar
Senior Member
Posts: 618
Joined: Fri Apr 02, 2010 5:08 am

Re: Towing regulations And recommendations

Postby kfxnando » Sun Jan 23, 2011 4:52 pm

dont know if this will help anything or just add to the confusion!!
however thing the latter will be true, at least to a certain degree!!

in the yard, had a close look at

1. Toyota Cressida

2. Ford Sierra

3. Ford 4x4

3. a spare towbar for a traylor, witch sooner or later will do duty!!!


Toyota and 4x4 tow balls are 27.7mm thick just below the tow ball

( the shank of which should be 22.2mm in diameter )

given this is not our standard!!

the one on the Sierra is 28.5, and the only thing that now stops me from grabbing that one for the 4X4 is the fact that that the car was hit from behind however not the towbar, so maybe after all it will be fine!!

here is the strange thing, there are no other marking on the tow balls, somehow seem to remember there being some marking behind the ball, where it mounts, under normal circumstance would not remove it to have a look at the marking, never mind now that am home recovering!!

and the strangest thing at this point is the only marking, on a TowBall is on the Toyota, it has a marking of 180kg
well just went back outside to double check , BIG BIG mistake!!!

after cleaning it good, found a SABS marking, and the 180 grew, its 1800KG

yep thats right!!!


the one on the 4x4 has no markings!!!

however the 4x4 has a GCM of 4160kg(however this just gets more complicated - later later) witch contradicts what the law says it can be
and it also exceeds what my license says I may drive!!

the one on the Cressida is clearly marked 1300kg

the one on the Sierra with a very similar goose neck coming out from under the car is marked 1325kg

the one on the towbar for the back of another traylor is marked 750kg, about the only one that makes sense!!

however, the tow bar on the 4x4 is of a much heavier construction, quiet posibly will take the 1.8 tons that the ball (appears to be able to handle) and the weight the traylor will end up being!!

come to think of it, the ball if used properly, actually not take that much stress, as when one jumps on the brakes, the traylor has its own brakes and thus the ball does not take the full stress of the weight of the traylor!!
thus a vehicle while towing a braked caravan/traylor has a shorter breaking time/distance then just the tow vehicle alone!!

hope this makes sense!!
User avatar
Senior Member
Posts: 618
Joined: Fri Apr 02, 2010 5:08 am

Re: Towing regulations And recommendations

Postby kfxnando » Sun Jan 23, 2011 4:55 pm

here is some more info on the RSA although it could be a little outdated!! ... VC8065.pdf
did have some more links saved on my laptops, however that has dies, Hardrive if fine, will post once info recovered!!

:mrgreen: :mrgreen:
User avatar
Senior Member
Posts: 618
Joined: Fri Apr 02, 2010 5:08 am

Return to Trailer

Who is online

Users browsing this forum: No registered users and 2 guests