What you need to know about motorhome weight
How to stay safe and legal
Motorhome weight doesn’t have to be confusing. And staying safe and legal is easier than you think. When you are new to motorhome ownership, there’s a lot of information to take in. But one of the most important things to understand is the impact of vehicle weight, load, and distribution on safety, drivability, and legality.
This guide provides everything you need to know, starting with laden weight.
Laden weight is a term used to refer to the weight of your motorhome when it’s full of people, gear, and equipment. However, if you overload a motorhome or put too much weight over either axle, the outcome can:
- restrict your ability to brake hard in an emergency
- significantly increase fuel consumption
- increase the potential to lose control when changing direction
- cause tyres to wear prematurely or fail
- lead to suspension failure
Moreover, you could land in trouble with the police by driving an overloaded vehicle.
Feeling like you need to take everything, including the proverbial kitchen sink, on holiday is commonplace on those early trips. But as time passes, you adapt with experience, especially when you feel the difference between the unladen motorhome you took delivery of and the fully laden and potentially overloaded one you took on your first holiday.
But before we explain weight limits, loading tips and tricks, here’s a refresher on the technical terms and supporting information:
Understanding MIRO, MTPLM and Payload
MIRO and MTPLM are abbreviations for describing motorhome weight and load.
MIRO (Mass In Running Order) is the unladen weight of your motorhome when it leaves the factory. The figure often includes a full or 90% fuel tank allowance and an average driver weight of 75kg. However, depending on the manufacturer, MIRO may consist of:
- a full gas bottle
- a full or empty water tank
- other items like a leisure battery
Every manufacturer calculates their MIRO differently, so double-check the small print in the handbook.
MTPLM (Maximum Permissible Laden Mass) represents the maximum safe weight when fully loaded, as defined by your motorhome’s manufacturer. MTPLM is also known as laden weight, GVW (gross vehicle weight), MAM (maximum authorised mass), MGVW maximum gross vehicle weight or maximum permissible laden mass)
Top Tip! Ideally, MIRO and MTPLM should be treated as minimum and maximum. And aim for a fully laden weight somewhere between the two numbers.
Another acronym to be aware of is GTW, which stands for gross train weight. GTW combines the maximum vehicle weight and a fully laden trailer.
Where to find the numbers
Everything is on the manufacturer’s weight plate, typically inside the driver’s door or under the bonnet.
However, more than one contributor may add a plate during the motorhome’s construction. These are known as stage plates:
- Stage 1: the base vehicle manufacturer such as Fiat, Ford or Mercedes may add the first plate
- Stage 2: you may also find a weight plate from the chassis manufacturer, such as AL-KO.
- Final: motorhome manufacturers such as Swift, Rapido, Dethleffs, or Bailey often add the final weight plate.
Top Tip! Each stage plate supersedes the previous one. The chassis manufacturer plate includes the MTLPM and the axle weight limits, and the motorhome manufacturer plate also provides the MIRO.
Here is an example of a chassis manufacturer’s weight plate:
The following example of a Bailey Motorhome weight plate includes the MIRO:
Payload
Your payload is the weight of everything loaded into the motorhome except the items accounted for in the manufacturer’s MIRO. A payload usually includes passengers (not the driver), leisure equipment like bikes, awnings and furniture, and equipment upgrades like extra gas bottles or a second leisure battery.
The easiest way to check your payload limit is to deduct the MIRO from the MTPLM.
In our Bailey Approach example, the maximum payload is 3850kg-3217kg=633kg.
How to check your motorhome’s laden weight
If you know the payload limit but exceed it, your laden weight exceeds its limit.
There are two ways to check your payload. First, you can weigh every item you intend to load. Or, second, you can drive your laden motorhome to a public weighbridge.
Weighing everything manually
Weighing every item might seem like a big task, but once you’ve done it once, you’ll have a record to guide you on every journey.
A record is especially helpful when you load more gear than others on trips. For example, you’ll pack more for a two-week holiday than a weekend. And you may pack extra clothes, water, gas and a second leisure battery if you go off the grid.
Check your motorhome at a weighbridge
When you need extra peace of mind, double-check your laden weight using a weighbridge — the GOV.UK website has a handy postcode checker to help you find your nearest weighbridge.
On arrival, drive forward so the motorhome wheels are on the weighing plate. Now, apply the handbrake and record the laden weight. At this point, it’s also wise to record the front and rear axle weights, especially if you have additional weight on the tail, such as a moped or small motorcycle.
Also, it’s a good idea to double-check the weight again if you subsequently make DIY upgrades, such as fitting extra appliances, installing solar panels, or stowing an awning.
Tips to lighten the load
Here’s a table showing how the typical weight of items that can soon add up:
To help lighten the load, list everything that’s essential versus nice to have. Then, look at ways to cut the travelling weight down, including:
Water supply
Empty the water tanks and refill your water supply on-site. This could save up to 150kg.
Food shopping
Carry the basics, but do the main food shopping closer to your destination.
Plates, cups and cutlery
Consider plastic plates and cutlery, or take the minimum needed. For example, you should only need a partial set of everything if there are two of you staying in the caravan.
Cooking utensils
Two cooking knives and two pans are much lighter than an entire set. Consider using aluminium pans rather than iron pots or steel.
Gas
A self-fill gas bottle is refillable at Autogas outlets. So you may not need to take a spare cylinder. You can also buy lightweight composite gas bottles to save weight.
Battery
Consider replacing your heavy lead-acid domestic batteries with high-performance Lithium versions. If you change two conventional batteries for a single Lithium unit, you could save up to 40kg.
Clothes and shoes
Clothing adds up surprisingly, especially shoes and winter coats. Do you really need to take three or four pairs of shoes for each person? And do you need two weeks’ worth of clothes for an extended stay when you could take a quick trip to the launderette?
That’s it. You now have the information to manage your laden weight correctly. You should be safe knowing that your motorhome will handle perfectly — and you won’t be breaking the law.
Happy motoring!