Towing Capacity

SJ, as has been stated, it's not really that confusing, there are certain weight limits that you legally can't exceed, and others that you sensibly shouldn't exceed.  First of all the legal ones:

Caravan MPTLM - This is the maximum that your caravan can weigh, including all your kit, awning, table, chairs etc.  You can't exceed this.  (And the best to find out what your van weighs is to take it to a weighbridge with your usual load... You may be surprised).

Car gross train weight (GTW), or gross combination weight - Usually found on a plate on the car somewhere, your Car & Caravan (trailer) together cannot exceed this weight.

Car gross vehicle weight (GVW), also known as Maximum Authorised Mass, should be on the same plate as the GTW - the car & all its contents, luggage, passengers etc. cannot exceed this figure.  (There should also be max axle weights for the front & rear axles of the car on this plate)

Noseweight - The tow ball, tow hitch & caravan chassis will all have a maximum nose weight, you cannot exceed the lowest of these figures

Now the sensible ones:

The cars maximum towing weight is usually the GTW minus the GVW.  E.G.  a GTW of 4000 Kg & a GVW of 2000 Kg in theory gives a max towing weight of 2000 Kg,  The car manufacture will quote a max towing weight, but that is usually only an indication of the cars ability to perform a hill start with a trailer hitched. (on a 1 in 12 slope I think) .  

However, it is unlikely that your car will weigh the GVW (unless you load it to the gunnels!), so if the weight of the car & contents is say only 1800 Kg, and you tow a caravan with a MPTLM of 2000Kg, you are towing at a ratio of over 110%, not recommended.  Therefore there is a recommendation of not exceeding an 85% ratio, hence people are recommending you look for a tow car around 1750 Kg.  (85% of 1750 = 1487).

Obviously all sorts of other factors affect how well the car/caravan combination perform, including loading, drivers experience & noseweight, SA or DA etc.  Some people will happily tow at over 85% & upto 100 & beyond, others will tell you not to even think about exceeding it. As long as you don't exceed the legal limits, it all comes down to how safe & confident you feel you can tow or handle your outfit.  However i would certainly be wary of towing a van weighing more than the car, even if legally the limits say I could.

One more thing, I would also check the max noseweight of any prospective car, (the higher the better, in your case you'd be looking at achieving a noseweight of between 75 KG & 100 Kg approx, (using 5-7% of 1468).

Hope the above helps.

Paul.

85% (mptlm of kerb weight) is not a 'rule' just a recommendation and is considered to be outdated by many.

Gross train weight and gross combination weight are not one and the same. Gross train weight is the actual weight of the car and the trailer when both are on the same weighbridge. It must not exceed the plated max. gross train weight. Gross combination weight is the sum of the plated max. GVW of the towing vehicle and the MTPLM of the trailer.

According to gov.uk, they are.  Now it won't be the first time gov.uk has been wrong, but lots of other sites state GTW & GCW are one and the same.

Either way, if the combined weight of the car & trailer when taken on a weigh bridge exceed the plated GTW, the combination will be classed as overweight. 

Correct, but gross combination weight only has any relevance with regard to Category B driving licence entitlement.

Example 1:

Car's GVW: 2000kg, plated max. Gross Train Weight: 3600kg

Trailer's MTPLM: 1650kg, but only loaded to 1400kg

= technically legal but needs a B+E licence (plated GTW is not exceeded but gross combination weight exceeds 3500kg)

Example 2:

Car's GVW: 2000kg, plated max. Gross Train Weight 3600kg

Trailer's MTPLM: 1400kg

= technically legal and OK with a Category B licence because the gross combination weight is less than 3500kg although the plated Gross Train Weight exceeds that figure.