What does MRO mean on a caravan?

In this article, we will explain: what does MRO mean on a caravan, what are the dangers of driving overloaded and how to properly load your caravan. 

What does MRO mean on a caravan?

MRO is short for Mass in Running Order of a caravan, also known as MIRO. In more simple terms, this is the weight of a caravan ready for the road as it leaves the factory. The MRO also includes the weight of:

  • Gas bottles;
  • The water in the toilet and heating system;
  • Hook-ups and the weight of the battery;
  • The driver’s weight (fixed at 75 kg);
  • The maximum levels of fuel, lubricants, coolants;
  • As well as the standard equipment (auxiliary wheel and tools).

What does MAM mean on a caravan?

To find out the Maximum Authorized Weight (MAM) of your car, please refer to the car’s manual. The MAM indicates the maximum authorised weight for your car and includes:

  • The curb weight of the car.
  • The weight of the luggage and equipment transported (bicycles, for example).
  • The weight of the transport accessories (roof box, bicycle rack, etc.).
  • The weight of the driver, his passengers and their 4-legged companions.

For an obvious safety issue, compliance with the maximum authorized weight is a road safety priority. Also, if you drive too heavily and the police find that your car does not meet its authorized GVWR, you risk a fine, or even a lot more.

How much do caravans weigh?

There are many myths in the caravan world about the weight that our vehicles have when they leave the factory, one of the most common problems in our sector. The origin of this problem lies in the maximum authorized weight in vehicles for drivers with a type B driving license, of 3,500 kg. For vehicles that exceed this weight, up to 7,500 kg, the C1 type license is required. 

Motorhome manufacturers, aware of the ease that it means for anyone to be able to drive a motorhome with the car license they already have, have always limited their vehicles to that weight. However, over the years, motorhomes are getting bigger and more equipped, while the legal limits remain the same as they were in the past.

In order to stay below that limit of 3,500 kg, manufacturers have been increasingly reducing the weight margins for the load, until reaching the current adjusted level of between 200 and 300 kg, which they consider sufficient to carry the people for whom the vehicle is authorized in the datasheet, but who do not take into account other equally important factors when starting up, such as accessories, luggage and the internal water load.

So how much does our caravan really weigh? 

If we take into account that, as soon as we buy our motorhome, we usually install, from the beginning, a large number of accessories such as supplementary batteries, the awning, the TV, the cooler, the antenna, the DVD, and a long etcetera, to what we must add the essential preparations for any trip, for which we will load two propane bottles and at least 100 litres of drinking water, in addition to clothes, personal belongings, kitchenware, sports equipment and others.

In the end, we have to the margin of 200 or 300 kg foreseen by the manufacturer is rather short, and that the total weight of our vehicle far exceeds the 3,500 kg of the maximum allowed load to circulate.

How dangerous is it to exceed the maximum allowed weight for a caravan

The overweight with which our vehicles circulate on many occasions had not been a serious problem so far, since the only weight checks that were carried out on our vehicles were those carried out during periodic technical inspections, times when normally they are checked. Motorhomes are free of charge and therefore comply with the legal limits.

However, law enforcement officials are increasingly demanding compliance with regulations and, logically, motorhome drivers cannot be ignored in this compliance. That is why it is increasingly common to see roadside checks in which the vehicle is weighed, revealing a reality that has lived with us for many years: that unfortunately many of us drive with excess weight, without even knowing it.

It is necessary to remember that driving with excess weight can lead to significant penalties and even immobilization of the vehicle. This problem is especially aggravated in some countries that exercise really strict weight control. 

Likewise, it should be remembered that, in many cases, in order not to exceed the legal maximum weight, the legalized seats do not correspond to those actually existing in the vehicle, and the fact of occupying them while driving is also a punishable fact. 

The biggest paradox of all this is: How can it be that our vehicles are approved to carry a maximum load of 3,500 kg when, in reality, their dimensions and capacities are designed to carry 4,000 kg?

The dangers of exceeding the maximum weight of your caravan

The danger of driving an overweight vehicle goes beyond a pure administrative penalty. We must bear in mind that the total weight of the vehicle is the sum of the weight of the vehicle and all its luggage, including passengers, luggage, car fluids and any other type of article that is transported in it.

The limitation in the datasheet does not only constitute a restriction on the mechanical resistance of the vehicle but also on the behaviour that said vehicle will have on the road. It is therefore very important to ensure that you do not exceed the maximum weight allowed by the vehicle manufacturer, as its behaviour above the limits imposed does not have to be verified.

There will be many who assure that, although the technical data sheet is limited, our vehicles are prepared to transport much more weight, reasoning that we do not doubt, but we must not forget that most manufacturers float their motorhomes on conventional industrial chassis.

On the other hand, we find in our trips many roads with weight restrictions for vehicles, to protect the weakest areas of the same, such as bridges or half-built areas, or to prevent damage to the structures located along the road. Driving with excess weight in the vehicle through them could make us incur a double danger, that of exceeding the limit of our vehicle as well as that of the road.

The bottom line

The bottom line is to respect the payload of your caravan and to not exceed the maximum allowed weight, as you will face severe penalties and you will put both your life and other’s lives at risk. 

Please let us know if you have any questions or comments on the content. 

FAQ on What does MRO mean on a caravan?

How is caravan payload calculated?

The payload of a caravan is calculated by subtracting the MRO from the van’s aggregate trailer mass. 

What caravan Weight Can I tow?

You can legally tow a caravan weight of 3500 kgs or 3.5 tonnes. Each car make and model have a specific towing limit for both braked and unbraked trailers.  

Can you increase a vehicle’s towing capacity?

You can’t increase a vehicle’s towing capacity as they are engineered with a specific capability. Some cars weren’t designed for towing at all!

How do you tell if you are towing too much?

You know that you are towing too much if you are over the GCWR and if your vehicle is leaning, or there is lots of bounce when you hit bumps along the road.


Was this helpful?

Thanks for your feedback!