Understanding motorhome weight

Motorhome weight is important. Exceeding your allowed motorhome weight or camper van weight can be dangerous, invalidate your insurance and warranty (if you have one) and even lead to a fine.

The motorhome weight also has a bearing on what type of driving licence you need, as explained here.

Information about your motorhome weight will be on a plate on your van, but understanding what these motorhome weight figures mean is another matter. In the UK the V5C (aka ‘log book’) will show the gross weight (see below), but not the other figures.

This post seeks to explain what all these motorhome weight figures mean.

Motorhome weights

New motorhome / camper van users often don’t realise that there are weight limitations on their vehicle – you’ve got a big van and it’s tempting to stock it up with all sorts of things. I was on my second van before I realised I should be aware of the weight issues.

And when you do realise, it’s not always easy to understand which weight figure refers to what. There is information on motorhome weights elsewhere on the internet but I’ve found most of it a bit sparse on detail. I’ve tried to include everything here, including how to weigh your van.

Motorhome plates

As noted above, there will be a plate on your van somewhere showing the various weight figures. In some it’s in the engine compartment, newer models may have it in one of the front door frames.

In fact, there are two in the engine compartment of my van, one from the vehicle manufacturer (Fiat) and one from the converter (Rapido), both with the same figures. This is the Fiat one.

On the following picture I’ve numbered the various rows, to explain them below:

1. Gross Vehicle Weight – this is the maximum weight you can go to, including contents, people etc. Also known as the Maximum Authorised Mass (MAM) or the Maximum Technically Permissible Laden Mass (MTPLM).

2. Gross Train Weight – this is the permissible total weight if you are towing something and is the sum of the Gross Vehicle Weight above and the weight of the towed item.

3. Front axle maximum weight – maximum weight on the front axle (obviously).

4. Rear axle maximum weight – as above for the rear axle.

5. Maximum weight for third axle, if you have one.

A word about weight and mass

The terminology around motorhome weights often also refers to ‘mass’, as in MAM above. Technically there are differences between mass and weight but unless you’re camping on a different planet with different gravity they can be considered the same thing.

Mass in Running Order (MIRO).

This is the weight of the motorhome at its standard specification, without things like gas bottles, food, clothes and other sundries. It may include water and fuel and the driver.

There should be a sizable difference between the MIRO and Gross Vehicle Weight to give you scope to put things in your van. For example, my MIRO is 2,750kg and my Gross Vehicle Weight is 3,300kg, so I’ve got 550kg to play with.

Weighing your van at a weighbridge

To check you are within the law you need know your Actual Laden Weight, which is the total weight with everything on board that you would take on a trip (including people). You need to ensure your Actual Laden Weight does not exceed the Gross Vehicle Weight (aka MAM or MTPLM).

This is done by loading the van with everything you would normally take (including filling the water and fuel tanks) and going to a public weighbridge.

You should be able to find the nearest public weighbridge by entering your postcode on the following government web page www.gov.uk/find-weighbridge. There will usually be a charge (my local one charges £15).

The weighbridge will issue with a certificate, which you should keep handy in case you need to show it to police etc.

Noseweight

If you’re towing something, you need to check the noseweight of the towed item – this being the downward force it imposes on the tow bar. Noseweight can be measured using a noseweight gauge.

Excessive noseweight can have a detrimental effect on stability and the recommended noseweight is 5-7% of the Actual Laden Weight of the motorhome.