Weights, Plates and Payloads

Why is weight important?

Absolutes and Variables. 

OK, lets start with the Absolutes: 

Driving Licences -

If you passed your car test before 1st January 1997, are under the age of 70 and have no medical conditions restricting your licence, you can drive a motorhome up to 7500kg Maximum Authorised Mass (MAM) or 8250kg with a trailer – that covers almost all British and European motorhomes, and some Americans too.

If you passed your car test after 1st January 1997, you are licenced to drive up to 3500kg MAM, or 4250kg with a trailer (the trailer must not exceed 750kg).  This will still enable you to drive the majority of motorhomes available on the market.  To drive vehicles of higher weight you must take an additional test. For more information, follow this link: DVLA, What Can You Drive

The 3500kg rule also applies once you reach age 70, unless you apply to the DVLA to retain your 7500kg entitlement.  This usually requires a medical; for more information, follow this link: New or Updated Licence

Motorhome Weight Plate Information -

Take a look at this Iveco weight plate:

In the highlighted area, there are four sets of numbers, each representing Kilograms.

4000kg is the Maximum Authorised Mass (MAM) that the motor home can be loaded to, also known as MTPLM or Maximum Technical Permissible Laden Mass, including fuel, passengers etc; in short, everything.

7000kg denotes the Gross Train Weight (GTW), which is the legal maximum combined weight of this vehicle and any trailer it is towing. As the difference between the MTPLM and the GTW in this instance is 3000kg, this is effectively the maximum trailer weight that can be towed by the base vehicle. It is wise to check with the motorhome manufacturer if considering a towbar, as many motorhomes have modified chassis which may affect the towing capability of the motorhome.

1800kg, also marked ‘1’ is the maximum weight on the first, (front) axle.  2600 is the maximum weight on the second (rear) axle.  Both these weights, when added together, come to more than the 4000kg MTPLM; this is to allow some flexibility in positioning of load on the chassis, but does not permit the total to exceed 4000kg, or to exceed the individual axle limit!

Here’s another example from a motorhome with an Al-Ko chassis:

The format is similar, MTPLM (Maximum Technical Permissible Laden Mass) for the vehicle, then the Gross Train Weight.  The difference is smaller this time, so this vehicle can only tow 1000kg.

Also, there is a third axle weight shown, as this plate is from a ‘tag axle’ motorhome, with a pair of rear axles, like this one:

Whatever motorhome you are buying, on whichever base chassis, there should always be a plate attached, with this basic weight information.

Variables:  So how much can I put in it?

At this point we know what we can load the motorhome to, but we don’t know where we are starting from, in order to work out how much margin we have for all our gear and passengers we want to take, otherwise known as ‘Payload’.

Mass in Running Order (MRO) is the term manufacturers often use in brochures and technical specifications, to give us a meaningful unladen weight of the motorhome.  The exact components within this calculated weight can vary, however the typical criteria adopted by numerous manufacturers is to EU regulation 92/21 as follows:

Manufacturers are allowed a build tolerance of +/-5% for component variation in production.

The usable payload is therefore the difference between the MRO and the MTPLM.  See example below:

Don’t forget:

So how much Payload do I need?

There is no straight answer to this, as it depends on what you want to do with the motorhome: A couple who go mountaineering will need more payload for their gear than a couple who like to relax in peaceful surroundings with a couple of comfortable chairs.  A family of 6 will need more than a family of 3.  As a very rough guide, allow 50kg each for the first two peoples’ personal effects, plus 25kg for each additional person.  So, in the hypothetical example above, the figures could look like this for a family of four:

The only way you are going to know for sure is to weigh everything:  A laborious and tedious task, which should only be necessary if you are concerned that the fully loaded motorhome may be overweight. 

By looking for motorhomes with generous payloads (taking into account what the MRO specification of the manufacturer concerned includes), you are less likely to have worries later on.  If your licence is restricted to 3500kg, then your payload considerations become even more important.  Generally speaking, the bigger the motorhome the heavier its MRO, and correspondingly less payload than a smaller motorhome if the Maximum Authorised Weight is 3500kg.

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