Towing weight, Which is legally correct?

ps: Why downplate the caravan? So long as the actual weights are less than all the plated ones there is no need to downplate. A car with a permissible towload of 1500kg could pull a trailer with a 2000kg MTPLM so long as the trailer's actual axle load doesn't exceed 1500kg AND so long as neither the GTW nor the car's MAM and permissible axle loads aren't exceeded.

So what you are actually stating, in the event of of an accident a manufactures warranty claim I can rely on your advice ?

I am with Lutz on this, and very specifically that "One should not fall into the trap that MAM + MTPLM = GTW."

MTPLM is a limit, not a weight and should not be used when calculating Gross train weight. 

GVW of the car is all load resting on the cars axles. That is (car, occupants and luggage + tow ball load). 

Towed mass is the weight of everything resting on the trailers axles. That is the total mass of the caravan - nose weight. 

Gross train weight includes everything ; actual mass of (car, occupants and luggage + tow ball load) + (actual weight of caravan - tow ball load). 

Case in point - if you have a tow bar mounted bike rack, is has no axle. The mass of the rack and bikes is entirely payload for the car. You are not towing the bike rack. You must be under the tow ball load, and under the GVW.  A car with no towing capacity (GTW = GVW, or not homologated for towing) can still (in theory) have a tow bar fitted for a bike rack perfectly legally. 

OM, I think what Lutz is saying is as long as you observe the rules you have nothing to worry about. 

Our van has an MTPLM of 1550, and max noseweight of 100. 

Our car has a max towed load of 1500 and towball load of 90. 

I don't need to down plate the max noseweight on the van to be under the max towball load of the car, just make sure it is actually no more than 90. 

The same is true for the towed load. I have to ensure that the towed mass is less than 1500. 

I can still load the caravan up to 1550, as I know that 90kg of that will be car payload, making my towed mass 1460. But I still have to be under the maximum mass on my car (GVW) and under the maximum train weight (GTW). 

Interestingly - my car has a specific clause in the manual that - when towing - allows the GVW to be exceeded by100kg as long as the speed is limited to 62mph. 

I.e. When towing caravan or trailer, the 90kg nose weight is allowed in addition to the non-towing GVW. The GTW MUST still be observed. 

It's not my advice. It's taken from the wording of the regulations, as referred to in legislation.

To put it simply, gross train weight is the sum of all axle loads of both the towing vehicle and the trailer. Gross vehicle weight is the sum of all axle loads of the vehicle in question. Hence, gross train weight minus gross vehicle weight is the trailer's axle load. MTPLM doesn't come into it, although even that mustn't be exceeded, but it doesn't enter into the equation.

But here lies the problem the CMC Technical 'Outfit Match' gives different guidance, is is down to their interpretation of regulations ?

CMC Technical 'Outfit Match' is not the law and I don't think that they even claim that it is. They are only trying to give advice on obtaining a good match, not on what is actually a legal limit.

I am in an almost identical situation. My car has a towing limit of 1500kg even though it weighs almost 2000kg. The caravan MTPLM is 1550kg and the nose weight limit is 70 kg or 80kg depending on which document from Toyota I look at. Even in the lowest nose weight the towed weight is below the cars towing limit and the outfit below the gross train wright. I carry in the car a print out of the relevant section of the document referred to by Lutz in case I am ever pulled over by Plodd so I can show that I am legal (assuming my weighing is correct). 

I have looked up https://www.legislation.gov.uk/eur/2012/1230 as referred to by Lutz.

Reading Article 2, Definitions, paragraph 7 states, “technically permissible maximum laden mass’ (M) means the maximum mass allocated to a vehicle on the basis of its construction features and its design performances; the technically permissible laden mass of a trailer or of a semi-trailer includes the static mass transferred to the towing vehicle when coupled;”

While I would love to gain an extra 90 or so kilograms of payload, the fact is that the weight borne by the tow bar is still to be included in the maximum technically permitted laden mass of the trailer.