Car Trailers - Technical Information - Coupling - Drawbar - Brakes


The coupling is what attaches the trailer to the towing vehicle’s towbar. Saris trailers are fitted with couplings from world renowned leading manufacturers ALKO or Knott. These are easy to operate and have built in safety features including wear indicators.

Hitch is open
Hitch is Closed


The smaller lighter trailers have a single T Shaped drawbar , while the larger heavier trailers have a heavy duty “V” Drawbar fitted. Some of the small trailers have the option of a “tipping” Drawbar and can have an optional Jockey wheel fitted also. The Larger “V” Drawbars have a Jockey wheel incorporated.

Independent Suspension

The state of the art Independent Rubber Suspension (IRS) Axle represents the benchmark in fully independent trailer suspension. Saris trailers are fitted with these Independent torsion suspensions from world renowned leading manufacturers ALKO or Knott.

The unique self-dampening characteristics of the rubber
element slow down the suspension rebound, which ensures a smooth ride over all types of road surfaces. Thanks to the independent suspension, each wheel springs independently – Bumps in the road therefore only have an effect on the side where they arise.

Independent Torsion Suspension

Rubber cords at either end of the beam offer independent suspension action and work similar to an inbuilt shock absorber effect providing a
self dampening nature to the suspension.

This axle system is now the benchmark for fully independent trailer suspension. The trend to independent suspension first revolutionised the passenger car, then four wheel drives and is now the choice for trailers too.

This improves stability of the trailer and reduces the risk of dangerous snaking under heavy loads.

Shock Absorbers

For an even smoother ride, some of the trailer models have the option of having shock absorbers installed on the axles.


Service Brake:

A Service brake or running brake in the trailer’s main braking system , during normal use. When the towing vehicle slows down or stops the trailer hitch coupling automatically applies the trailer’s brake, so assisting the combined vehicle in decelerating . This hitch is known as the “Overrun Device” and its components are outlined in the diagram below. Saris trailers are fitted with an Auto reverse feature that will automatically allow normal reversing without the brakes applying. Trailers over 750kG must have such a braking system

Trailer Braking system
Alko Axle , Braked

On this single axle braked trailer, the braking force is evenly distributed to both wheel hubs via 2 brake cables.

On a multiple axle trailer, the braking force is balanced out and is applied to all trailer wheels.

Parking Brake:

A Parking brake or hand brake is a mechanism to activate the braking system which is used to prevent the trailer from rolling when parked. This may consist of a toothed lock mechanism, activated and released with a push button lever. On the larger Saris Trailers , a spring loaded handbrake lever is used which is easily applied and released and is easy to operate to control braking on an unhitched trailer moving downhill.

Breakaway / Run Away Brake

This is a device that can automatically stop the trailer if it becomes detached from the towing vehicle when in motion. When you attach your trailer hitch to your towing vehicle, you also attach the breakaway cable to a special bracket on the hitch assembly or loop the breakaway cable over the hitch. The red coated steel cable on the hitch photo below is the trailer’s breakaway cable,


Breakaway Cable

If the trailer becomes detached from the towing vehicle while in motion, a pulling force will be exerted on the breakaway cable and it will engage the run away brake , and so bring the detached trailer to a stop.

Secondary Coupling

Trailers up to 750Kg , which do not require a braking system, must have a secondary coupling system fitted. This is usually a chain or wire rope attached to the trailer drawbar which is looped over the towing vehicle’s hitch.. If the main coupling fails or becomes detached this will keep the trailer attached to the towing vehicle and from touching the ground until the vehicle can safely come to a stop.

Jockey Wheel

The jockey wheel is an adjustable drawbar support wheel that is fitted to many large trailers and is also available as an option on lighter trailers. It allows easy manual raising and lowering of the trailer drawbar hitch when coupling and uncoupling the trailer and the towing vehicle. This is of particular use when the trailer is loaded. It also allows easier manual movement of trailers when unhitched. Once finished using the jockey wheel in can easily be completely raised from its working position and clamped in its stowed position

Prop Stands

These are drop down stands to support the trailer when uncoupled or for stability when loading and unloading. On larger heavier trailers, these stands are lowered and raised by a crank mechanism.

Mesh Sides / Leaf Rack

Many of the trailers can be fitted with mesh sides which will allow the trailer to be used for a whole host of applications from gardening to trips to the recycling centre. These are east to fit and remove. A cargo net is also available to cover the load.


Only available on modern cars.

7 Pin Adaptor

All Saris trailers have the required lights fitted and come with a 13 pin plug. Modern cars are equipped with a similar 13pin socket to take this plug. We have 13 – 7 pin adaptors available for towing vehicles that have the older 7 pin socket fitted. (When using this adaptor, the trailer’s reversing light will not be operative.

Vinyl Covers

A Flat Vinyl cover can be fitted to many of the trailers to cover the cargo within and also to protect the trailer from the weather elements, when not in use. A number of the trailers also have a high vinyl option supported on a steel frame to create an enclosed protected cargo area.


Check out this valuable RSA booklet on towing trailers.


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