As many of you know, I sold my Class A motorhome and have been looking at trailers. As usual, before I wandered off looking, I sat down and listed what I wanted in a unit. In the "must have" picture, it had to weigh less than 5,000 pounds fully loaded, had to have a metal (steel or aluminium) upper frame with plastic outer skin construction, be "Arctic Insulated" including windows, be wired for solar power, and had to maximize potable, grey and black water capacity.

In the "wants" department, it had to be built to sleep only two (in one bed), have roof air, convection/microwave, no oven, Fan-Tastic vent, largest fridge possible, bathtub in the shower, and have maximum storage space. In the "would be nice" department, an inside screen door, floor night lighting, an exterior shower, levelling jacks, someplace for a generator, jalousie windows, lots of battery capacity, and an interior décor that did not remind me of a place in Nevada. I also sketched out several possible layouts that would accommodate a travelling office. This took some thought, but after a few drawings, I had a good idea of what I wanted. I then started trawling the dealer's yards.

Finding a unit that had my "must haves" was not difficult, although water capacities were less than I had hoped, and solar power less available than I expected. I quickly found a number of aluminium-framed units in the 20- to 25-foot range that would do. In the "wants department", it was a little more difficult as I could not find a unit only built to sleep two, although I could find units that either had everything else that I wanted - or that could be added, like roof air for example.

In the "would be nice", except for the jalousie windows, I also could find what I wanted. However, no trailer had a layout that would accommodate a travelling office. One dealer in Winnipeg did point out that one of his units could be modified to both only sleep two, and have a travelling office. Jalousie windows could also be fitted, but they were expensive to have made. With that, I turned to the actual mechanical stuff.

And here, I must admit, I was shocked. After crawling under a number of units, I discovered that the norm was simply an axle or two, supporting a trailer on leaf springs. No shocks, no sway bars, no panhard rode, no radius rods, no nuthin'! My buddy Albert said in his experience, other than equalization hitches, trailer suspension systems had not changed since he had started pulling trailers, and Albert is older than dirt. Another buddy, who is a fiver hauler, suggested that I look at fivers, since they may suit my needs. And so I discovered that a fiver's suspension is no better.

And so you ask, "Why the concern? There are millions of these rigs on the highways." That's true, however as front-wheel drive replaced rear-wheel drive as a better package solution, perhaps it is time to adjust our thinking on trailer suspension. Rough Country, a division of Walker, started with the introduction of trailer shocks. I know from many hundreds of thousands of miles of driving that a tightly, well-suspended car, truck, or motorhome is safer, more controllable, and much more pleasant to travel in than a poorly suspended unit. Couple this poor equipment with an inexperienced driver, and trouble is just waiting.

We all have seen, and many of us have towed, a unit bobbing and weaving down the road. Just yesterday, I followed a large trailer down rough Highway 18 in Manitoba, during a stiff quartering NW wind. Even though the tow rig was a large, heavy, dual-wheel pickup, the driver was clearly struggling to stay in his lane.

To understand why this is such a problem, you have to understand some of the dynamics involved with suspended units. First, the wheels travel up and down as they encounter obstacles on the road, causing the unit to also travel up and down. Second, the wheels on each side can go up and down independently, causing the unit to rock from side-to-side. As both actions usually occur together, the unit simultaneously moves vertically and rocks from side-to-side. Third, as the unit is snubbed at the front with the trailer hitch, the trailer's motion is further distorted and the trailer will also pitch (the front moves up and down less than the rear). The vertical motion will further be distorted if the unit is loaded (or built) such that the majority of the weight is not over the wheels, but is toward the rear or is located high up in the unit.

Real problems can occur if the weight is at the rear, AND is offset to one side. This is one reason why you are cautioned to not travel with full tanks. Finally, fourth, as the wheels encounter big or small obstacles on the road, they have a tendency to hesitate before rolling over the obstacle, causing the leaf springs to distort. This is because the trailer tires are usually inflated to a very high pressure, severely reducing the tires' ability to absorb bumps and forcing the springs to respond instead.

When the wheels are clear of the obstacle, the springs resume their correct shape and the wheel snaps forward. This motion is transmitted to the unit as fore and aft loading, and is often felt in the tow vehicle as if the trailer is loose on the ball hitch. While all this foolishness is happening because of road conditions, the wind and passing vehicles are also acting on your trailer. Your unit then gets a double whammy, and the results are white knuckles, broken springs, and smashed dishes.

As if this were not enough, the motion of the trailer is transmitted to the towing unit through the hitch. The rear of the tow vehicle is pushed up and down, and sideways, loading and unloading the rear suspension (and to a degree the front suspension), and the trailer may also impart a fore and aft loading on the tow vehicle. To further confuse the issue, the tow vehicle itself moves in response to road and wind conditions, and imparts those movements back to the trailer through the hitch. To really compound the issue for the driver, because the tow vehicle is usually heavily loaded and has the trailer hitch weight at the rear, ITS suspension is less able to control the vehicles' movements than the driver is used to.

Take all of the above, add in an inexperienced driver, (just how many times and miles do you really tow your trailer?) and it is easy to wonder why we do not see more problems on the roads.

To solve some of theses problems, the equalization hitch was invented. I should point out that other types of hitches were designed, and built, but I am only going to discuss the ball hitch, as it is by far the most popular. In effect the equalization hitch turns the trailer/tow vehicle combination into one unit in the vertical plane.

To illustrate: Put two spoons end-to-end on the table then pretend that one is your trailer and the other your tow rig. If where they meet is the trailer ball, then it is easy to see that the tow rig can pivot about the hitch, as can the trailer. The equalization hitch consists of two heavy spring steel bars that connect the units in the vertical plane only. Thus the vertical movement of the trailer part of the hitch, or the tow unit part of the hitch, is also transmitted to the other side of the ball hitch. If the trailer half of the hitch rises up, the vehicle part does too.

Now put a knife on the table beside the spoons, and lift up on the back of the trailer end of the spoon and the knife. You can see that with the spoons, the pivot point is the hitch, and with the knife, the pivot point is the front wheels of the tow rig! The trailer weight and the tow rig weight have been cross-transmitted to the other vehicle's suspension, or "equalized" between the units.

The net effect of this is to restrict the adverse vertical effects of the trailer or the tow rig pitching being transmitted to the other rig. In other words, the up and down movement of the trailer half of the hitch caused by all the suspension inadequacies outlines earlier, are much reduced. At least in the vertical plane, the tail no longer wags the dog. The combined units ride easier, and are therefore easier and more pleasant to drive. Note that this does not solve all the problems. All the sideways and fore and aft movements are still there, and still have to be dealt with.

And that we will discuss next time. By C.J. Vermeulen