Trailers have been in existence since decades. They are seen everywhere; airports, factories and even in backyards. Most of them function at limited speeds and within controlled environment except travel trailers and semi-trailers (Cargo) which typically operate on interstates and other open roads.
Travel trailers are integrated, customized, non-powered, extended, aero-dynamic cabins or mobile homes made from sheet metal or reinforced plastic material and attached to powered vehicle through hitch which typically consists of ball and socket assembly. This engineering piece consists of several parts, all of which have a definite purpose. However, this form of towing system does not prevent swaying of the trailer which brings up an important question; what is trailer swaying?
Trailer swaying is an uncontrolled movement of the trailer, typically sideways caused by cross winds, poorly designed hitch, or improper suspension of the trailer.
In the classic ball and socket assembly the ball is mounted on a draw bar which is fitted to the trailer hitch through pinning mechanism. The entire accessory is naked and can be seen hanging between the tow car and the trailer.
Swaying trailers are being dangerous and cause accidents, which brings up yet another question. Why do vacationers buy them? Why not simply purchase a powered luxury home on wheels. The answer is cost. These vehicles cost a bomb and cannot be used for day to day travel. On the other hand your regular car can be used to tow a trailer which is available at a fraction of the cost of a luxurious motor home.
Coming back to the trailer sway issue, every trailer owner knows about this unrestrained lateral movement which occurs while overtaking or when another vehicle passes by. Sway results in accidents which may vary in intensity; from minor brush to the trailer actually toppling over. The sway occurs because of uneven weight distribution and also because of free motion in the hitch assembly.
Many of us have seen them toppled over or badly damaged, hanging at the side of some interstate highway waiting for help. This scene is not unusual because almost 10 to 12 % of trailer owners have at some point in time faced this situation. Many of them are shaken so badly that once they get back home, they simply dispose off their trailer at throwaway price.
Sway can be minimized with the below mentioned tweaks. However, by fine tuning you as the owner can only minimize the sway and not eliminate it completely.
1. Low quality, thin, frictionless tires which have little or no sidewall protection can increase the sway. The idea is to fit trailers with appropriate tires.
2. Uneven weight distribution is one of the major causes for sway syndrome. Fine tune this metric for a better ride.
3. Long hitches, made from light weight material, and based on obsolete technology can make a trailer sway dangerously. Check the dimensions before fitting one.
4. The length of the trailer also plays an important role in the sway factor. It simply means; longer the body more the sway.
5. Tongue weight – Around 10% of your trailer weight should be on the tongue or the pivot point. It means the trailer should be parallel to the road and not dipping either in the front or at the back.
Many new hitches have come into the market each claiming to reduce the sway to almost 0%. However, the truth is regular sway control hitch or sway control parts can only minimize the sway but not eliminate. These standard weight-distribution systems will just curb or suppress to a point. The friction in the sway control hitch will be overpowered at some point in time by the forces built at the side of the trailer.
One way of eliminating the sway is by shifting the pivot point which plays an important role in the towing assembly. The idea is to form a cohesive unit. The free movement of coupling mechanism is thereby harnessed which otherwise results in major sway.
So what is the solution and how can sway be eliminated completely? One way of doing it is by shifting the pivot point of the assembly to the rear axle of the towing vehicle. This translates into a join which is highly controlled, effective in terms of maneuverability and reduces the sideway drag drastically.
By transferring the pivot point forward, the drag between the two (the tow car and the trailer) is reduced and at the same time a cohesive unit is formed. However, on the negative side the hitch has to be mounted permanently on the tow vehicle which might put off some owners.
This form of hitch assembly although costs more but it pays for itself in the long run because of its built quality and technology, which means reduced maintenance and reduced chances of minor and major accidents thereby saving enormous amounts of money in repairs, insurance and injuries. On the other hand friction based sway dampening hitch assembly cannot eliminate the sideway movement completely. The choice depends on your budget and of course on your inclination towards safety. Moreover because these assemblies are cheaper than the pivot point transfer system many trailer owners are tempted to opt for them. In spite of its limitations it continues to remain a popular option.
Most of the campers and camping enthusiasts mostly look at the design, the interiors, furnishings and other décor when they shop for trailer. Very rarely do the buyers talk or ask about the hitch or the assembly which joins the tow car and the trailer. It is human nature. No one wants to look at some ugly, black metal assembly which literally sticks out like a sore thumb. The fact remains that you may select a designer trailer without a safe and a perfectly engineered hitch. In such a scenario you are putting yourself and others at risk.
Weight-distribution systems or sway control mechanisms have evolved to a great extent in the recent times. These new generation hitches are based on single or dual cam system, and available in the following avatars.
1. Independent sway control.
2. Dependant sway control.
3. Active sway control.