Camper Trailers Tech Tips

off-road couplings

 

 

off-road couplings

The majority of members in the Australian CamperTrailers Group own an off-road vehicle together with a purpose built off-road camper trailer & prefer to venture off the beaten track into the more remote parts of Australia. For this reason they have an off-road tow coupling which suits the capabilities of both vehicle & camper. Let's look at what off-road hitches are on the market & what sort of job they do.

 

 An on-road BALL COUPLING has limited movement & therefore is not generally suited to off-road use. This diagram on left shows the limited vertical movement. Major trouble can develop with this type of coupling off-road if the tongue bottoms out into the hitches casting & breaks a piece out of the coupling, rendering it useless.  Ball couplings as shown right with hydraulic over-rider brakes have a 360 degree swivel sideways.

   

The PINTLE HOOK has its origins in agriculture & then developed for military purposes in the 1940's. The pintle coupling is not as popular as it once was.  It does have limited movement from side to side & can be noisy at times over rough terrain.

 

An improvement on the Pintle Hook is Vehicle Components VC COUPLING which represents a major breakthrough in the performance of ring type couplings. The key to its ingenious design is separating the ball movement from the clamp.

The coupling locks a conventional ring into place so there is no play in-between the towing vehicle and the trailer. The base of the coupling incorporates a sealed ball joint which provides the articulation between the two vehicles.

As the movement is fully sealed the coupling can be used in arduous conditions needing no maintenance. It does not experience the excessive wear that a pintle hook and ring gets in such conditions.

The lack of play in the coupling eliminates noise and damage between the vehicle and trailer and does not snag when reversing around tight situations.

 

 Next comes the TREG type coupling which also includes the similar TRIGG hitch.  It does have a pin that stops full up & down movement, but this does not seem to worry it. It has full 360 degree movement from side to side. This type of hitch with its poly block is the most popular of the modern hitches today.

 

The polyurethane block gives some shock absorbing properties, stops noise & vibration from the trailer to the vehicle. Over 50 percent of members of the CamperTrailers Group own a Treg coupling. 

 

 The ORAC type coupling has full vertical  movement, ( shown on left) & full 360 degrees sideways movement as well. It is of similar design to the HOLLAND hitch. (At time of writing it can not be verified if Holland hitches are still made.)

 

                      

 Another off-road hitch is the HYLAND, pictured left, which uses a ball coupling with a difference. The hitch is manufactured to give the ball full articulation. It also has full 360 degree sideways swivel & is far superior to the old ball hitch in off-road situations.

 The Hyland hitch must be used in conjunction with a 3.5 tonne ball which has a higher stem than the standard 2.5 tonne ball. This allows for proper fitment of the Hyland hitch over the ball allowing clearance without fowling the tow tongue. 
 

 

The AT35 COUPLING (now discontinued) has a secondary means of automatically locking the primary locking mechanism in place. It is rated at 3.5 tonnes capacity.

This coupling incorporates variable rate polyurethane bushes which absorb shock yet allow the structure to take the maximum loading condition. Articulation is high (70 deg min) in all combinations of movement.

The low profile design allows maximum clearance for rear opening doors and can be fitted with most stabilizer systems. The
Vehicle Components standard handbrake is designed to fit to the rear mounting bolts of the coupling.

An over-ride version of this coupling has been discontinued because the volume of sales was not viable. There had not been one single warranty claim.

 

HITCHMASTER DO25 Drop On 2.5 tonne, is a new design in off road couplings by Vehicle Components.  The two diameter pin & boss arrangement makes it easy to connect just like a ball coupling. The chamfered area between the two diameters makes the pin slide through the hole in the coupling at whatever angle the hitch may be.

The DO25 has a simple hooking up procedure, just pull the T bar up & rotate until the locking plate moves in under the pins head. Simply letting go will let the location pin on the locking plate drop into its hole & at the same time the spring lock fixes the locking plate also. The Vehicle Components DO25 coupling has been discontinued.

 

HITCHMASTER DO35 Drop On 3.5 tonne, is a bigger version of the DO25 which was released earlier this year. The DO35 is rated at 3.5 tonne & has  the same safety features as the DO25 with two separate locking mechanisms.

The machined surfaces makes hitching up much easier in awkward locations than other off road couplings that need a pin to be inserted. There is a small poly block for shock absorption between the trailer & tow vehicle.

 

The HITCHMASTER DO35 V2 is the result of continuous improvement & rigorous testing by Vehicle Components. It is rated for a maximum load capacity of 3.5 tonnes and complies with the Australian Design Rules 62/01 and 62/02. The coupling has a polyurethane bush on the pin, a double locking mechanism and a sleek safety cap which doubles as a visual aid to ensure the locks are engaged. It is very simple & easy to connect even on uneven ground. Off road it has full 360 degree rotation & 70 degree articulation. It is suited to all camper trailers and caravans for off and on road usage.

   

 The OzHitch is a simple drop in off-road hitch with a self aligning tool in the shape of a cradle which lines up perfectly the two halves of the tow hitch for easy connection. This trailer hitch has some great advantages in being low profile, fully bushed so no rattles, ADR accredited, lockable for security, galvanised option and connects in 15 seconds. There are two locking mechanisms and they only take one hand to operate leaving the other hand to operate the jockey wheel. The hitches design allows for 85 degrees of movement up and 70 degrees in a downward direction.

 

UNIGLIDE The McHitch Uniglide Trailer Coupling uses a universal joint to handle all of movements well past 90 degrees horizontally and vertically with the twisting being handled in the rear body by shock absorbing urethane bushes. The universal joint is the same found in all 4wd Landcruisers while the joint is held in place by registers and opposite threaded plugs & end caps which removes any end play. The universal and rear body are both fully greaseable.

 

 AL-KO has released three new off road couplings onto the market which fit a towball. They feature a patented positive towball latching system that make connecting a breeze, requiring no pin or hole alignment. The couplings are ADR compliant meeting Australian Standards & designed & tested in Australia for Australian conditions. The three versions available are a 2 tonne and 3.5 tonne fixed intended for used with electric brakes & a 2 tonne overrider for mechanical or hydraulic braking systems. All feature 360 degree head articulation. 

 

HITCH-EZY is an Australian designed easy to connect off road coupling new on the market. Articulation is 90 degrees up and down with 360 degrees rotation. The automatic double locking mechanism is easily to released even with one finger using the incorporated arthritis aid. The hitch can also be driven while pad locked. Urethane bushes in the main shaft provide rattle free operation while O-ring seals keep dust and water out. Rated at 5,000kg.   

 

 

information by Rob

updated december 2013

 

 

 

NATHAN HITCH