Dan TrudgianSee other Advice articles filed in ‘General caravan advice’ written by Dan Trudgian
On the side of every caravan are some details that are essential to understand, and which ensure the caravan is both safe and legal.
Commonly referred to as “the plate”, the information can vary from each manufacturer, but details such as the correct tyre size, tyre pressure, recommended noseweight and even the awning size can be displayed here.
No two manufacturers display the same information in the same way.
However, as a legal minimum, all caravans will have the following information clearly displayed.
Know your weights
Broken down into two areas, the plate will include weight values and the VIN (vehicle identification number).
For now let’s focus on the weight values.
All the weights displayed are measured in kilograms (kg). Two weights appear on the plate and these will be marked as MiRO and MTPLM.
But what do they mean and why are these important?
What’s the MiRO?
MiRO or Mass in Running Order is the weight of the standard caravan with no payload.
It does include the weight of a gas bottle, a fresh water tank 90% full of water and the flush tank full of water.
It doesn’t include the weight value of a leisure battery, but does include the weight of an EHU cable.
What does MTPLM mean?
MTPLM stands for Maximum Technically Permitted Laden Mass.
This value was created by the manufacturer and is the MiRO plus your user payload. You cannot exceed this value.
If you are towing a caravan and the weight exceeds the MTPLM, not only are you exceeding what the caravan was designed to carry, but you can void any warranty, invalidate any insurance and, even worse, you will be breaking the law!
This possibly will not be displayed on the plate, but it is an important figure nevertheless.
You can calculate your payload like this:
MTPLM – MiRO = payload
To ensure your payload is within your allowance, it’s a good idea to weigh everything that goes into the caravan.
You can do this by using a set of bathroom scales. Simply weigh yourself and then, with the items you wish to stow away in the caravan, weigh yourself all over again.
One more thing...
There is a final complication, however: the MiRO does not include caravan accessories.
These can be items such as motor movers, aftermarket solar panels, axle jacking points etc.
These are add-on items that were not fitted as part of the core product when the caravan left the factory (please note, this does not include dealer special edition caravans – you need to consult the dealership you bought the van from to obtain the available payload).
However, there is a handy way of staying legal, though... Read on!
How to stay legal on the road
Let’s say a caravan has an MTPLM of 1485kg and a MiRO of 1294kg.
This gives a healthy payload of 191kg, which is more than enough to include clothing, bedding, an awning and miscellaneous items for a family of four for a week.
However, this particular caravan has had a motor mover fitted and an optional extra solar panel which must be deducted from the payload figure.
Our 191kg payload has now shrunk by 38kg, leaving 153kg for personal belongings. Unless you know the weight of every accessory fitted to the van, calculating the available payload could be quite complicated.
The solution is to weigh the caravan. Visit one of the many private or council-run weighbridges around the country and for a small fee weigh the van with no liquid in any tank, but with a gas bottle, leisure battery and EHU cable on board.
You will then be given the actual weight of the caravan. Use this value as your starting point, deduct it from your MTPLM and you will have a payload figure unique to your caravan.
Help, I'm overweight!
But what if what you have in the caravan exceeds your payload?
This is when tough decisions need to be made. You may have to relocate some of the items – either in the car, in a roof box or just by leaving them at home.
Of course, if you do move some items to the car, you must ensure that you are within the correct weight limits of the car and within any restrictions of your driving licence.
Finally, if you are looking at new or used caravans for sale in search of your next tourer, pay attention to the available payload and, if needed, take a calculator to understand what you are likely to stow away.
As a visual guide, recall the likely luggage limit you will get on an airline – this varies between 20kg and 40kg and is the size of a well-packed suitcase.