Probably not as much as you think!
Start by ignoring any salesman's assurances or published figures, the only way to be sure is to work it out for yourself. The payload is the maximum weight of everything you can carry in a vehicle without exceeding the maximum it's legally allowed to weigh.
The first thing to check is the maximum your motorhome can weigh. This is limited by the manufacturer to ensure that the vehicle can be operated safely
To find this figure you need to check the VIN plate. This is the manufacturers plate, often located under the bonnet, it might also be a label stuck to a door frame or riveted to the side of the body somewhere.
On this plate you will see the VIN (vehicle identification number or chassis number) along with a series of weights in kg
The first of these is the MAM (Maximum Authorised Mass), this is the maximum that the motorhome is allowed to weigh, go over this weight and you run the risk of being pulled over for overloading. If seriously overloaded, you may not be able to continue until the excess weight has been removed.
The second figure is the MTW (Maximum Train Weight) that's the maximum that the motorhome plus any trailer can weigh.
The third figure is the maximum weight that the front axle can carry, the fourth is the maximum that the rear axle can carry. If it's a tag-axle motorhome there will be a fifth figure for the second rear axle.
You'll notice that if you add up the individual axle weights they come to more that the MAM, this is to allow for uneven loading.
So, now you know your maximum permitted weights you need to check what the actual figures are.
For this you'll need to visit a weighbridge. Your local Trading Standards will have a list, or you can find your nearest ones here: https://www.gov.uk/find-weighbridge You will need to check the total weight and the weights for the individual axles.
Ideally you should weigh your motorhome in its 'ready to travel' state with everything you normally take with you on board, including yourself and any passengers! That way you'll know whether or not you're legal on the road.
An overload on one axle can often be corrected by shifting stored items forward or back depending on which axle is overloaded. If you are over the MAM you'll need to take some stuff out! For example, if you usually travel with a full water tank of 100 litres, emptying it will save you 100kg.
Some vehicles can have their MAM uprated so that they can carry more weight. This may just be a paper exercise or may involve suspension and tyre upgrades. Check with the experts to see what's possible
Be aware that taking the MAM over 3500kg will mean that you need Category C1 on your driving licence. Most people who passed their test before 1 January 1997 will have a C1 licence, this entitles them to drive a vehicle up to 7500kg, from this date the standard driving test only provides for driving a vehicle of up to 3500kg
Happy 'safe' travels......
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