Moving a tandem axle trailer

By Dimo: May 18, 2007
Topics: Trailer Towing | No Comments »
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An individual who owns a very large RV was trying to make a sharp turn into the intended parking spot using a powered trailer mover. Here’s some specs on the RV.

  • Length 29′ 9″
  • Axle weight 4,206 pounds
  • Hitch weight 700 pounds
  • Tandem axle trailer with 205/75 R15 tires.
  • Tandem axle trailer with 205/75 R15 tires.

In the process of parking, using the trailer mover, it became necessary to position the trailer mover at an extreme angle to the tongue of the RV, approximately 70°. He applied power and nothing happened and wondered why. It was as if he were trying to push through a brick wall.

To fully understand the dynamics of what is happening here, it is beneficial to first drop back and look at what happens when a single axle trailer is turned and exactly what is happening in the process. Let’s look at a quick drawing (excuse my lack of artistic skills) and see if this can explain what you are dealing with.
 

When a trailer mover is positioned at a 90° angle to the tongue of a trailer or for that matter, 60°, 50° or even 40°, a single axle trailer simply rotates on one wheel or the pivot point (see YELLOW X) and the opposite wheel follows the outside arc of the turning radius. No mess, no fuss and no problem. It all happens and works in a very smooth and orderly fashion.

However the same situation, this time with a tandem axle trailer, presents a host of different problems and what was a ridiculously easy thing to do with the single axle trailer is a much more involved process. Let’s look at another drawing to try and understand what is going on.

 

If a RV trailer had a personality it would, at this point, be a personality under great stress for you have placed it in a real quandary. Before, with a single axle, it was an easy task to decide the pivot point or “Axis of rotation”. But here, we’ve changed the equation significantly because neither set of inside wheels can become the pivot point and form this axis. Therefore a point somewhere in between the two axles has become the axis of rotation and we now have a war going on between the tires of one axle against the tires of the other axle. It’s a no win situation!

With the trailer mover pushing in the direction of the blue arrow, this has set up a situation where the outside tire of the front axle is doing its best to follow the arc of the intended radius of movement. The culprit here becomes the rear axle. Its tires are forced to move in the direction of the red arrow and can do nothing but drag sideways along the surface. The tires of the front axle are dragging in the direction of that red arrow.

It is possible to make the trailer move given enough force being applied to the tongue but this will never be done with a small trailer mover such as those being sold in the market today. It would take the power of a truck and in all likelihood, it would apply so much force to the frame of the trailer that a tire or tires could become dismounted from the rims or at worse, the axle hubs could be bent. So this take us to the next step.

How do you turn a tandem axle trailer with a trailer mover?

Actually, given enough space for maneuvering (and this is critical), a tandem axle RV or boat trailer can be easily turned and parked most anywhere you wish to park it. It’s not a fast process however it can be done by one of two methods. (Editor’s note: If someone knows of another, please send it in.)

First Method:

Generally, in most cases, a large tandem axle RV can be easily repositioned (this case a 90° turn) in one continuous movement. To do this, imagine a 100′ X 100′ box shaped area. Beginning in the lower left corner of the box, you can swing around to the upper right corner of the box by positioning your trailer mover handle at an angle of between 15° to 20° to the center line of the trailer tongue. Press you power switch to ON and begin moving.

In this instance, while there is still some slight drag on the tires, there is enough rotation (movement) of the tires so that you will not notice it. The tires are taking a little bit of the arc of the curve with each turn of the tire. Too much angle on the handle and the tire drag increases dramatically (as in the previous drawing example). The move is made in a sweeping giant smooth arc.

Okay . . . . so you don’t have 10,000 open square feet of paved surface. What’s next?

The first method was the best of all worlds solution. Now let’s look at the real world.

Second Method:

Most of us park our tandem axle boat or RV in a much more confined area as we do not have a parking space rivaling that of a shopping center parking lot. However, you must have sufficient maneuvering room of almost twice the length of your RV.

Starting at your beginning point, commence a move such as you would start in the wide arching movement in the first method. It makes no real difference if you begin by pushing or pulling your trailer. Put as much angle on your mover handle so as to allow the trailer move without the tires noticeably dragging and inhibiting your progress. The tighter the turn, the better but do not overdo it! Move back about ½ the length of your RV, turning as you do.

Now, reverse the handle to the other side and push or pull the same distance placing your RV at an even greater angle to your beginning point. Repeat this process as often as necessary to end up in the direction you intended to place your trailer.

This sound vaguely familiar to getting out of a tight parallel parking space?

You are right! It’s simply a process of making the direction change in small incremental back and forth movements instead of one single movement.

There is an old question; “How do you eat an elephant?”

The answer . . . . Very carefully and one bite at a time.

 

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