Caravan Weight Distribution - updated December 2018
Caravan weight distribution is a critical issue. When you place too much weight at either end of a caravan, it degrades the rig's. Here, RV Books explains in simple terms why this is a problem and what can be done to ensure it does not become a serious problem.
Caravan Weight Distribution - test this yourself!
This simple test instantly shows what happens when too much weight is placed at either end of a moving caravan. All you need are two weights - each about of 3-4 kg. Anything will do.
Stand, with your feet slightly apart, holding the weights close together. Now rotate quickly to one side (either will do) and stop. You will find it easy to do.
Then repeat the movement as above - but with the weights held out as far as you can from your sides. You will find it much harder to stop. Do not try this with heavier weights as it then becomes may find it extremely hard to stop - and you can be thrown over.
This is the caravan swaying equivalent. If centre-heavy is relatively easy to stop sway forces from affecting the caravan.
If however the caravan is end heavy it will initially resist swaying. If it does so, however, restraining that sway is very much harder. It may start to sway to and fro dangerously. All that can restrain it is the tow vehicle's mass and grip of that tow vehicle's rear tyres. If sway forces exceed that ability, that rig is likely to jack-knife.
This shows why you should never put heavy items at either end of a caravan. This is particularly so for its rear - as there is nothing at that end to restrain the typically violent movement.
Avoid locating anything heavy at the front (and particularly) the extreme rear of your caravan. That includes spare wheels, toolboxes, bicycles, motorcycles, spare water and fuel canisters, extra batteries, generators and BBQs. If placed at either end of a caravan, these items become just like the weights at the end of the bar of the rotating weightlifter.
A major trap with end-heavy caravans is that, like oil tankers and car ferries, they seem (and are) ultra-stable whilst travelling in a straight line. But if subject to a sufficient side force, such as a suden strong gust of wind or attempting an emergency swerve, excess weight at either end of the caravan overwhelms the restraining forces. Sway rapidly escalates and the rig jack-knifes.
RV Books strongly recommends placing all heavy items as close to the caravan’s axle(s) as possible.
Weight and Speed Distribution Experiment
The adverse effects of Incorrect weight distribution is strongly related to the rig's speed. Even a seriously end-heavy caravan may seem stable below an often critical speed. That this is so is shown by the most common first comments of a caravanner whose rig has jack-knifed. It is 'my rig has always felt totally stable - until then'.
To illustrate this, Dr. Jos Darling of the University of Bath in the UK developed an experiment, in partnership with Bailey Caravans UK, to demonstrate the effect of incorrect weight distribution on trailer stability.
Watch Dr Darling's video (below)to see how weight distribution affects trailer stability:
Caravan Weight Distribution - that ideal
The diagram below shows where you should place light, medium and heavy items in a caravan for maximum towing stability:
Motor Home Weight Distribution
Motor homes (and fifth-wheel caravans) are far less susceptible to incorrect weight distribution as long as all such weight is within the vehicle originally intended loading area. Nevertheless is it still advisable to place heavy items low down in the middle of a motor home. Use a motor home roof rack for light items only. Never locate anything except bedding in the over-the-cab peak sleeping area of any campervan or motor home.
Securing all items is critical in a motor home because goods and passengers share the same space.
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