What type of towball or hitch is best?
I want to tow; how do I know what tow bar or tow hitch I should use?
There are a few different types of towing connectors for passenger vehicles.
All types must comply with the Australian Standards AS 4177.
Tow bars fitted to the tow vehicle must comply.
Different revisions will include a variation on the Australian Standard number for example the AS 4177.1 and the AS 4177.4
I think everyone knows the 50mm standard ball type.
The coupling on the trailer for the 50mm standard ball must comply with the Australian Standard AS 4177
Some more specialty types have different features that may or may not be what you’re looking for or need.
The Offroad Polly Block gives a greater range of movement allowing a better offroad experience, but from my experience, they are harder to line up when inserting the pin through the block.
The DO35 is an easier connection, than the poly block, it is easier to line up when connecting and does self center when lowering onto the tow point. It is probably slightly harder to get lined up than the 50mm standard ball but it has the same articulation as the Poly Block type connection.
Remember that you must use rated shackles (Australian Standard AS 2741) that are suitable for the ATM of the caravan when towing vehicles in Australia.
Be sure not to overload your tow vehicle or caravan, check out our post about GVM, GCM, and ATM.
My Story
On my tow vehicle, I have a tow bar that uses a 2 inch receiver tube.
This allows me to change the hitch very quickly. It takes less than 60 seconds to remove and replace from one hitch type to another.
I have different hitches, I have a 50mm standard ball on a 3000KG rated tow hitch and the DO35 on a 3,500KG rated tow hitch.
I have a 3,400KG caravan that has a DO35 connection and a 750KG soft floor camper trailer with the 50mm standard ball.
I also have a recovery hitch, that can also be inserted into the same receiver for recovery of Toyota Landcruiser, Hilux, Jeeps, etc.
Tow Hitch type and Range of Motion
I have connected the goose neck to the camper trailer and caravan while not connected to the tow vehicle.
This will give me an easy way to show the articulation without the need to move the car and trailer/caravan.
There are 4 main ways in which the angle of the tow vehicle and trailer/caravan can be limited by the standard 50mm ball.
If we assume the tow vehicle and trailer/caravan start on a flat level ground and start moving forward:
1. As the front of your tow vehicle starts to go up a hill, we get the tow hitch dipping low. I’ll call this to dip angle.
2. As the front of the tow vehicle starts going down a hill, we get the tow hitch arching up. I’ll call this the arch angle.
3. As the left of the tow vehicle gets lower than the right by driving across a slope to the left the trailer will flex to the right. I’ll call this the right flex angle.
4. As the right of the tow vehicle gets lower than the left by driving across a slope to the right the trailer will flex to the left. I’ll call this the left flex angle.
Standard 50mm ball
Range of Motion
You can see from the photos below the range of motion of the 2 hitches I have.
The first one is my standard 50mm tow ball and the camper trailer.
The arch angle is restricted by the tongue of the gooseneck hitting against the trailer drawbar.
It appears the 30° range of motion is the limit of the 50mm standard ball.
You can also get 50mm standard couplings that allow limitless flex, which I do not have.
I have also added a few photos and a quick video of the path taken for the limit of articulation with the camper trailer below. As you can see this does allow some extreme off-roading before the limit of 30° articulation is reached.
If you only drive on gazetted roads, I feel that the 50mm standard ball is all that is needed.
DO35 Hitch
Range of Motion
The images below are of my caravan using the DO35 hitch.
As you can see the arch angle is around 45°, this is more than 2x the camper. This too is limited by the goose neck touching the coupling.
The dip angle is so flexible that the tow vehicle and the caravan would be able to smash into each other.
Think of the photo above, there is no way I would take my caravan through the gully like I have done with the camper trailer as the length of the caravan would get wedged between the 2 sides of the gully. Is this hitch necessary on a large caravan?
The left and right flex angle is limitless. There is a possibility that if the caravan or tow vehicle is rolling over then reaching the limit of articulation could force the other to also roll over. Having limitless flex hopefully means that only one will roll over and the other may be able to remain upright, and with this, I would not change this hitch to a standard 50mm ball connection.
Recovery Hitch
The recovery hitch can be a point of contention about what should be used and how to use it.
Soft shackles, cable dampeners, and nylon winch rope all make the process safer, but there is always a risk.
Think about the potentials.
If you are using a wire winch cable, it can hold a lot of potential energy when pulling a vehicle, if something breaks then the cable recoils, releasing that energy as velocity or movement. It can break glass, skin, bones, dent metal etc.
The nylon winch cable can still recoil but it is designed not to stretch, and the recoil will be minimal.
Snatch straps can be used to allow another vehicle to pull the stuck vehicle out of where they are stuck. Snatch straps are designed to stretch, increasing the potential energy stored in the strap. One of 2 things will happen, either the required potential energy is reached, and the stuck vehicle is pulled from the place where it has been stuck. Or something breaks, either the strap itself or the point at which the strap is attached to the vehicle.
If this has been connected to a 50mm standard tow ball the ball can break sending the ball flying. Think of this as a cannonball.
If connected to a steel shackle it too can be shot across the air, breaking glass, skin, bones, or even metal.
Always attach snatch straps and winch cables to rated recovery points.
Always use cable dampeners on cables to slow down the recoil of wire cables, snatch straps and even nylon winch cables. Dampeners can also dampen the flying steel shackles, but you are always safest to use a soft shackle.