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Don’t Level A Trailer With Jacks At The Corners

For Tiny Homes and RV Trailers, making your trailer level is important.  We get questions like:  I want to level my trailer when I park it, so what is the best way?  Should I use jacks at the corners?

This is a great question with several intertwined caveats on how to level a trailer.  These also apply with how to jack up or lift a trailer.  We will dive into several “Better” solutions and the reasoning for why (and when) one way is better than others.  Although the theory is really the same, the practical logic is different for a Tiny House Trailer, versus an RV Trailer, versus a Utility Trailer (open or enclosed).

We will start by looking first at the theory, then we can examine some practical differences.

Level A Trailer?  The Theory

When we look at a trailer ready to tow, Where is the trailer weight?  On the wheels and tongue.  The same when it is rolling down the highway.

When we park the trailer and level it, where is the weight?  OK, that is a bit of a trick question.  So, the typical way to level a trailer is to put jacks near the corners.  As we jack at the corners, it takes weight off the wheels, and tongue (or tongue jack).

To illustrate the point I will use this situation in the extreme (as I have seen in several RV campgrounds).  Some people jack so much on the trailer corners that the weight is almost off the trailer wheels.  (Note, for a Tiny House, you want all the weight off the wheels, because you do not want the house to sag as tires lose air pressure – which they all do eventually).

Here are a couple images showing how the loading wants to go.  These images exaggerate bending for a visual effect, yet they are directionally correct.

First, we set the stage and look at a 3D view of just the trailer frame.  This is a theoretical evenly distribution of load on a relatively long tandem axle trailer in a condition as it is going down the road.  We will call it towing mode.

Trailer Frame Loading 3D View

Now we can look at the Side View of this same trailer frame in towing mode.

Side View Trailer Loads

Notice the shape that is largely curved with the middle high.  Of course, this is grossly exaggerated by 25 times the actual bend, so it is easy to visualize.  However, this is really a normal trailer and normal loading.  Yes, the frames do flex, but more like 1 inch instead of 25 inches like shown here.

Level A Trailer with Jacks at the Corners

Next, we show the same Side View of the trailer frame held by 4 jacks, one in each corner of the frame.  This is an extreme case trying to level a trailer and lifting all the weight off the wheels.  Yes, this is a little obnoxious, but keep reading as we explain.

Level a Trailer with Corner Jacks

The key points to note are these:

  1. The shape of deflection.  Note that this curve is the opposite direction from when the trailer is towing.  That puts a lot of stress on the portions above the frame, like the walls and roof of your RV.
  2. The same load that is fine when towing will break the frame when lifting the trailer at the 4 corners.

OK, we understand that lifting the entire RV off the wheels is not the norm.  (Though not far off, because failures like this do happen.)  Anyway, we can do something a little more realistic to level a trailer without removing all the weight from the wheels.

Corner Jacks and Suspension

This view is more realistic as it puts 50% of the weight on the wheels, and 50% of the weight on the corner jacks.  (By the way, you do not need to lift the chassis very much to take 50% off the wheels.)

Please note that the stresses are much lower so the frame will not fail, but it still has the opposite-ish shape from when you are towing.  Still not good.

How Should We Level A Trailer?

As we see above, it is not a good idea to jack up a trailer at the corners – especially if there is a load in the trailer.  In the images above we see that corner jacks put a significant load on the frame, and in a direction opposite of the way it is when towing.

A better way to level a trailer is to distribute the load such that there is some counterbalancing around the jacks.  By coming in a bit from each end for the jacking point, the distribution of stress changes dramatically.  In the images above we see that jacks at the corners caused the trailer frame to fail.  However, if we move those 4 jacks in the appropriate amount, the effect on the trailer frame is much different.

Level a Trailer with Jacks Moved In.

Yes, this is the same trailer frame, with the same full load.  The axles support no load – effectively off the ground.  What a difference placement makes!

The key points to note are these:

  1. The shape of deflection.  Note that this curve is different than when the trailer is towing, but not grossly different – like the upside-down shape of using jacks at the corners.  This puts much less stress on the upper portions like the walls and roof of your RV.
  2. The same load that is fine when towing is still fine when lifting the trailer at these 4 inboard locations – even if you lift it so the wheels are off the ground.

A More Realistic View

OK, we understand that lifting the entire RV off the wheels is not the norm.  (Though not far off, because I have seen a few.)  However, this is very common for a tiny house.  Anyway, here is something more realistic to level a trailer without removing all the weight from the wheels.

Jacks Plus Suspension

Here is a more ideal case for an RV.  This moves the jacks out a little bit from the image shown just above, and it includes some weight on the tandem axles.

The key points to note are these:

  1. The shape of deflection.  The deflection here is the least of all the conditions.  That makes this way to level a trailer the least stress.
  2. The same load that is fine when towing is well distributed when stopped and leveling in this manner.

So, if you want to level a trailer, don’t use the corners.  That is the theory, along with a some practical thoughts.

The above analysis is based on consistent beams front to back.  The Beam Shape does not really matter, the trends are the same if the beams are consistent.

Thinking About The Analysis Results

If you think about it, when you pull the trailer the stresses are in a way that would make it bend, of course not nearly as dramatically, but like a banana with the ends down.  When you jack it from the corners, you are effectively flipping the banana upside down so the ends of the trailer are up.  You will not notice much in terms of measuring it, but it will be enough to create cracks in the shell or cause squeaks if you are not careful.

Of course all the different construction techniques for the shell compensate a bit for this.  However, conceptually, it is not a great idea to build it with the bending one way then level the trailer by it making bend the other way.  And really, the solution for that is so simple.  Move the jacks.

Just to be clear, there is nothing wrong with jacking it at the ends for stabilizing.  Just make sure MOST of the weight remains on the axle.

Yet, we see from the graphics above, that moving the jacks inboard a little (along the main trailer beams) with do the job better.  You can stabilize the trailer, and reduce frame stress at the same time.  That is the best.

The Effect Of Trailer Length

Length of the trailer makes a big difference with regard to this discussion.  An 8 ft long teardrop trailer will not likely have enough deflection to make a difference.  On the other hand, for a 30 ft trailer, it can make inches difference in deflection.  Basically, the longer the trailer, the more important this concept to level a trailer becomes.

This is also true for Tiny Homes.  Many of them get pretty long – like explained for our very popular 32′ Tiny Home (Updated).

Leveling An RV Trailer

As we say at the beginning of this article, the theory for leveling an RV trailer is really the same as for a Tiny House, but there are some practical differences worth discussing.

The most important difference is wheels on the ground.  With an RV we do not typically park to live in it for a long time.  We go, we enjoy, then come home.  Sure, full-time RVers often stay a while, so take this with a grain of salt.  On the other hand, Tiny Homes usually park and stay for a long time – often years.

With an RV, you can depend on the wheels to support the trailer for a stay of a few weeks.  Mostly, tires will not lose much pressure in that time.  So, looking at the images above (and the alternate technique below), the ones which show Axles supporting part of the load as you level a trailer will work.  This is preferred for an RV – especially since RV frames tend to be a bit weak anyway.

A Tiny House Foundation

On the other hand, for a tiny house, we recommend lifting all load off the tires.  Then, deliberately reduce the tire pressure.  Oh, and cover the tires!  These are all things to help avoid tire failure in the future.  So, with a Tiny Home, we must support the trailer frame more deliberately as we level it.  In this case, you can put 4 jacks as shown in the one image above, or – more reasonably, put in 8 or 10 jacks, or piers, to make sure the trailer frame is well supported – for weather and earth incidents more than for relieving stress in the trailer frame.

When using more than 4 anchor points, make 4 the primary ones (like in the image above), then use subsequent anchors to solidify the footing.

Side note, we also recommend to tie your tiny house down.  Yes, attach it solid – either with piers that the house rests on (and bolts to), or with some mighty ground anchors (like ground screws).  High winds, snow loads, tornados, micro-bursts, earth movement, etc, can all have a horrible effect on a home.  Mitigate some of that risk by anchoring the house solid.

We like to call the Tiny House frame the “Foundation” – because that is the function if performs.  When the Tiny House frame is really solid like in our Tiny Home Trailer Plans, then having a lot of support is less important for the frame.  Anchoring to the ground then becomes more or less of a task depending on the climate where your Tiny House is located.

As part of being a foundation, the way to level a trailer for a tiny house should be more substantial – which will probably cost more too.

Making It Easy To Level A Trailer

The next obvious question:  If not at the trailer corners, then where do we put the leveling jacks?

The exact perfect place is hard to figure out.  You must know exactly the weight distribution within the trailer.  Not very practical for most people.  So, here are 2 gross rules of thumb:

  1. In the 4 jack scenario where the tires are not touching the ground – think Tiny House – see the above image.  Come in about 20% from each end of the trailer.  15% is not enough, and usually 25% is too much.  So that gives you some parameters.  Make your judgement about how weight is distributed in the trailer – AND – what is structurally appropriate on the frame to lift from.  (Gotta be practical.)Measure to Jack Position
  2. In the scenario where wheels are on the ground and supporting significant weight (like 50%), then make your measurements based on the distance between the end (or front) of the trailer, and the nearest axle.  Place the jacks 30% in from the end (30% of the distance from the end to the nearest axle).  That means the jacks in front of the wheels are farther from the wheels than jacks behind the wheels.Jack Position

These 2 concepts differ because one leaves a significant load on the wheels, and one lifts the wheels entirely off the ground.

Another Approach For An RV

There is another option for jacking to level a trailer like an RV.  In effect we want to sort of simulate the support of the axles and tongue as it rolls down the highway.  We put the front set of jacks at the front corners, and the rear set of jacks as close behind as practical to the wheels.  Usually this means immediately behind the rear axle.  (Not advised for triple axles.)

Alternate RV Jack Positions

The idea is to keep the towing deflection shape, yet use jacks to level the trailer.  This also assumes significant weight still on the wheels – in the case of the analysis above that is 50% of weight still on the axles.  That means if the area where the RV is parked is not very level, use ramp block or something under the wheels to get the trailer close to level, then use the jacks to adjust the last little bit.

It can also work if you put all the weight on the jacks, but there is more center deflection.  In general the shape of deflection stays similar to that of the trailer towing, which is the advantage of this jack placement technique.

We do not generally recommend this approach for a tiny home since the other option leaves much less overall stress and deflection in the tiny house frame.

What If You Have Been Told Different?

There is a lot of opinion about the best way to level a trailer.  There is a good argument about maximizing stability by setting the jacks at the most extreme points (corners) of the trailer.  Yes, I get it, and if you are trying to stabilize it, you are correct – as long as you keep significant weight on the axles.

This article is about leveling a trailer.  Most of the time, that means lifting one side of the trailer or the other – at least a little bit.  Trailers are flexible creatures, and if they are really heavy, they will move around when we start jacking them.  The importance of jack placement completely depends on your value in taking care of the frame.

What I present is the simple physics for the purposes of education.  The colored images are engineering analysis, so it is not just off-the-cuff spew.  This analysis does ignore the upper envelope (walls and such) and the magnitude is exaggerated.  Yet, the concepts are directionally correct.  Please use this info if you find it valuable, or disregard it.

I am open to other ways to level a trailer, so if you disagree, please let us know in the comments.  Please include graphics and a good explanation so we can all understand.  After all, we want to learn from you as well.  Thank you.

What else?  What have I missed?

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