Updated April 2017

The maximum caravan weight safe to tow depends on what tows it. This article by Collyn Rivers explains why – and how to know what it is.

In earlier times, caravan weight safe to tow was assumed to be about that or less than the towing vehicle. But most caravans then were 3.5 to 4 metres long, weighed 900-1200 kg, and rarely towed above 80 km/h. Where that length and weight still applies, such trailer/tow vehicle weight remains fine. It is true of (sanely laden) camper trailers. 

With caravans longer than 4 metres, the maximum caravan weight safe to tow is more complex. With these, limiting weight largely relates to where the weight is distributed along the caravan’s length. This applies both to design and loading.

Caravan weight safe to tow – why this matters

Feel for yourself why this matters.

Hang any suitable bar (a broom handle will do at a pinch) by a rope. Add a couple of weights as shown below.

bar-simulation-closeThis bar simulates a caravan with the weight close to its centre. Hold the bar and turn it – like a caravan swaying. You will find that, even with heavy weights, it turns and stops turning with ease. Pics: caravanandmotorhomebooks.com

Now try it with the weights like this:

bar simulation web wideThis simulates an end heavy caravan exactly the same weight. Hold and turn it as before. You will find it surprisingly hard to start and stop.

The further apart the weights, the harder it is to start and stop moving. Also, (as with a tow vehicle and caravan) the lighter you are, relative to the length of the bar and position of the weights, the harder it is to stop and start moving. Take care if you try this with heavier weights. The force may push you over! The same applies if you use a longer bar.

Try it also with a heavier weight at the rear.

Caravan weight safe to tow – moments along a beam

Why this happens is to do with so-called ‘Moments along a Beam’. You can see this effect below.

 

seesaw

The ‘effect’ of weight on a pivoted beam (and a caravan chassis) relates to its distance from the pivot (axle). Pic: original source unknown.

 As you can feel with this bar, unless weight is more or less central, a short heavy van is safer to tow than a long van of the same weight. The see-saw effect also shows it is not good to have anything heavy at either end. Locate tool boxes, batteries, spare wheels etc as close to the axle/s. Never at the far ends.

You have some control over this. The heavier whatever you load, the closer it needs to be to the axles. Never load heavy stuff up front and ‘balance’ that by heavy stuff at the rear.

Because of the effects that you can feel for yourself, an end-heavy ‘van needs a much heavier tow vehicle than a centre-heavy ‘van the same length. Some locally made ‘vans are (in my opinion) far too long and end-heavy to be towed safely by anything short of the big Ford 250s etc.

Caravan weight safe to tow – relates also to caravan length 

You should have no problem towing a correctly laden 3.5 metre caravan by laden tow vehicle the same weight. But you are pushing your luck with a 6 to 6.5 metre end-heavy local product. I would only tow it with a vehicle at least 30% heavier.

If seeking a caravan longer than 7 metres I seriously advise readers to consider the dynamically more stable fifth-wheel caravan format.

For a warning and explanation of why many caravans are overweight see Caravan tare weight issues/

A more technical explanation is at: Caravan and tow-vehicle dynamics/ 

Information on tow ball mass is at: Caravan nose weight/

See also Why caravans roll over – also Reducing caravan sway. For info on fifth-wheelers see Fifth-wheel caravans are safer/

If you find this article helpful you will find my books even more so. They include the Camper Trailer Book, Caravan & Motorhome Electrics, Solar That Really Works for RVs), Solar Success (for home and property systems), and the all new Caravan & Motorhome Book. For information about the author – see Bio. 

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