MarkWrd1 wrote:
Would I be correct in saying GVW +MTPLM=MAM?
Hello Mark,
Welcome to the wonderful world of towing weights masses, and limits. The devil is in the detail, which the Government internet portal doesn't always make clear.
I do agree on first contact with towing weights and limits it can be very confusing. Its made even more difficult because the same criteria can be described by several different acronyms, and the differences between limits and measured values are not always immediately clear and understood.
There are some acronyms that might appear to have very similar definitions, yet one may refer to a measured value whilst the other may be a limit, and it doesn't help that a large proportion of the population do not appreciate the difference between mass and weight and force.
But despite its apparent complexity there is logic behind it, is a matter of working through it step by step.
However back to your question. Tow vehicles and trailers have separate Maximum Authorised Mass's or MAM's.
In your example the GVW is the same as the MAM for the car, and the MTPLM is the MAM for the caravan.
The wording of the licences B entitlement allows you to drive a vehicle whose MAM does not exceed 3500kg but it also allows you to drive a vehicle towing a braked trailer provided the combined MAM (GVW +MTPLM) does not exceed 3500kg. The important word is "combined". As Clive has pointed out you cannot circumvent the regulation by only part loading the car or its trailer as its based on maximum limits not measured weights.
Going for the E extension test removes virtually all restrictions and you can tow any trailer within the stated capability of the tow vehicle.
The law does not differentiate caravans from any other sort of trailer, but the caravan industry does offer guidance and suggests the novices should aim to have a caravan with a n MTPLM of no greater than 85% of the tow vehicles kerb weight, provided its within the vehicles towing specification. Only as experience is gained should larger percentages be tried topping out at 100%
I do not know which version of the DVLA advice you have read, but this is one area of the Governments portal which has been changed several times, and it it often fails to include important details that are particularly important to caravanners.