Loosing control of your towing rig while driving is a nightmare that you don't want to come true. A common control problem with travel trailers is the sway that occurs with wind gusts or passing big rigs. You can minimize the effects of trailer sway and make for a more enjoyable driving experience with just a bit of planning and preparation. Know how to evaluate equipment options and how to maintain and trim your rig by gaining an understanding of what causes sway and how it can be controlled.
See also Understanding Trailer Sway.
the default sway control installed by dealers is one or two simple friction bars. These have brake pads mounted to the tongue of the trailer and a bar connected to a small ball beside the hitch ball that slides through the braking pads. These work for most folks most of the time - at least for safety. They are relatively inexpensive and serve as a base level for inhibiting loss of control problems due to trailer sway.
There are no magic bullets. Abrupt maneuvers, especially at speed, may cause loss of control no matter the hitch or sway control mechanism.
Sway is a suspension problem. The suspension on your rig greatly influences its handling. When you have problems with control of your vehicle, whether a trailer rig or even a sports car, the suspension and its related considerations is always the place to start.
When travel trailers weighed under a ton and were under fifteen feet long, a bumper hitch was all that was really needed because the weight and strength of the tow vehicle just overwhelmed any influence the trailer might have (as long as the trailer weight balance provided good hitch weight). Now, with trailers running over four tons and thirty feet, they are larger and heavier than their tow vehicles and some accommodations need to be made for safe towing.
The first thing to do is to make sure that your running gear is well maintained and up to the task at hand.
Second is to make sure that your load is properly distributed side to side as well as front to back. This does not mean evenly distributed because a proper distribution means the heaviest loads are above the axles and there is a ten to fifteen percent of trailer weight on its tongue.
Third is to use a hitching apparatus appropriate for your needs that will help you keep and maintain control of your rig.
Fourth is to drive your rig with respect to its weight and handling.
See the page on hitch parts for information about terminology and function of the parts and pieces used to connect a trailer to a tow vehicle. The choice of the method used to attach the trailer to the tow vehicle determines how and where the trailer rotation forces are handled. All of these except the Pullrite expect you to have a properly rated hitch receiver bolted to the frame of your tow vehicle.
Draw-Tite (has a good page on weight distribution hitches and the dual cam) and EAZ Lift ("Over four decades ago, Eaz-Lift became the first patented weight distributing trailer hitch in North America.") are what you will normally find as the basic weight distributing hitch source for most RV shops. A brake type friction control may be added for sway control.
Pullrite - http://www.pullrite.com/principle.html - This moderately expensive hitch extends the trailer frame up to a point at the center of the rear axle using a special track on the tow vehicle to help support the vertical hitch load. The result is trailer towing with fifth wheel characteristics.
Hensley Arrow - http://divtune.com/hensley/ - http://www.hensleymfg.com/arrowdetails.htm - This expensive hitch uses a standard 2 inch receiver on the tow vehicle. Instead of a simple pivot point, this hitch uses a trapezoidal linkage that creates a virtual pivot point well forward of the hitch point for small angles.
Dual Cam - http://www.reesehitch.com/sway_control.html - This hitch uses a damping mechanism that uses a 'return to straight' force derived from a cam system. This damping mechanism depends upon spring bar loading and there are reports that much better handling is achieved when the spring bar load ratings are closely matched to the actual hitch weight.
Equalizer - http://www.equalizerhitch.com/ - The spring bars on this hitch provide friction damping as the trailer turns around the pivot point.
Blue Ox -Blue Ox Weight Distributing Hitches - OFX: Home Page - TruCenter Sway Control from Blue Ox Towing Products
The running gear includes tires, suspension, shock absorbers, brakes, bearings, and the other parts that are vital to keeping your rig rolling down the road. These must be chosen to support and manage the loads you will put on them. Maintenance is important to assure reliable operation. Tires must be properly inflated and checked before each run. Check the torque on lug nuts. Make sure the bearings don't run hot by checking wheel temperatures after twenty minutes or so on the road.
Besides the obvious fact that you should not put more stuff in your rig than it is specified to handle, you also need to make sure that this load is properly distributed so that each tire carries an even share of the load. The trailer should have about fifteen percent of its weight towards the front to be supported by the hitch. A load leveling hitch uses levers to move this weight to all four tow vehicle tires and the trailer tires by using spring bars that work against hitch point drooping.
It is also a good idea to try to keep leverage in mind when you load your rig. Keep the heavy part of the trailer load over the axles so that any sway has minimal mass at larger distances.
The key to driving safely with a trailer is to avoid abrupt maneuvers, especially at speed. Loss of control is most likely when reacting to something like a big rig blowing by or a car cutting in front of you or finding a surprise in the road. An attentive driver can anticipate most of these problems and take early action to minimize their effect. The driver should also train to be able to respond properly. For many drivers, driving with the trailer is only a small part of the driving experience. This means that most reactions and experiences are without a large rig and trailer on behind. It takes some effort to adjust to the needs of large vehicles towing trailers, especially when there is no time to think.
Trailer Towing - Hitch & Sway Control at disney.com - good pictures and illustrations of the various brand name hitches
Sunline Coach Controlling Sway - a Bill Estes column
RV Technology Weight and Balance - http://www.rvtechnology.com/weight___balance.html
http://www.hitchcorner.com/weight_distribution.htm for a catalog of load equalizing hitches.
GMC Towing - http://www.drivegmc.ca/Trailer.htm
Eastern Marine Technical Towing Information - http://www.easternmarine.com/em_showroom/tech_info/hitches_tech_info.html
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