Hello Dave

Welcome to the forum.

I appologise now for the length of this reply, but I suspect you do not realise the multiplicity of issues you have raised. I have composed several versions of my reply, but they all seem to get very long, becasue your assumptions are not quite correct, and the devil is in the detail which despite Mel's protestations is complex.

But lets try.

I own a Golf estate that weighs 1385 kg.

You do not tell us what the 1385 kg represents, Is it the cars Unladen Weight. Kerb Weight Gross Vehicle Weight?

I'm interested in several caravan models where the specified MTPLM exceed 85 % of my car's weight. However, the specified "base" weight (i.e. caravan without any payload) of those caravans are less than 85 % of my car's weight.

I understand the specified MTPLM is the weight of the caravan + max permissible payload weight. However, if I were to *limit *the max payload to a mass that, when combined with the caravan weight, did not exceed the limits for my car (in effect setting my own - lower than specified - MTPLM )

You seem to be labouring under the impression that towed weights are based on a percentage of the car's weight. This is not correct. Each model car has its own specifications about what it can weigh and what it can tow, so you need to review the details of your car to establish what it can legally do.

The Gross Train Weight minus the Gross Vehicle Weight from the cars data plate can be used to calculate the Maximum Towed Weight Limit for when the car is fully loaded. Most manufactures do use this as their maximum towed weight limit but not all:

Some manufacturers do set a greater braked towed weight limit but you do have to reduce the load in the car to keep the outfits total measured weight within the cars Gross Train Weight limit.

However these limits are derived from vehicle testing, using an

**ideal **trailer, but unfortunately caravans are not ideal trailers, which is why it is sensible to derate the cars towed limit for caravans.

This is where the UK caravan industry has fudged the issue by advicing for novices to keep the caravans weight less than 85% of the car's kerbweight, and only increasing towards 100% of kerbweight for experienced tugger's - but this advice is strange becasue it does not take into account the cars actual rating so you always need to check the advice does not go beyond the cars legal weight limits.

But considering your suggestion of using a caravan with an MTPLM that exceeds the "car's weight" runs the danger of discovering you don't have enough payload capacity left in the caravan. Consider the payload in most caravans is only 10 to perhaps 15% of the caravan's MTPLM, if you can't use 5% of the caravans MTPLM becasue of your cars limitation, you have lost between 33 and 50% of your payload capacity and you might find that unworkable.

1. If I limited the payload such that caravan + payload did not exceed 85 % of the car, this would be safe?

There are no such guarantees. Simply relying on weight ratios cannot guarantee safety. there's far more to consider. You need to ensure

- The car and caravan are in mechanically tip top condition,
- With the correct tyre pressures.
- Correct load distribution to create and adequate noseload.
- Understanding how the dynamics of towing change the characteristics of a vehicle.
- Driving with due care for the weather and road conditions,
- Understanding the prevailing speed limits for cars towing caravans, and
- Too much speed is always factor when outfits experience instability,

2. If I limited the payload such that caravan + payload did not exceed 100 % of the car, this would be *legal*? In other words, is the legal threshold based on the *specified *MTPLM even if you do not "use" anywhere near that limit, or on the *actual *weight of caravan + payload?

Your logic is wrong. The legality of towed weights is not based on a simple 100% ratio it is derived from the cars specifications and the limits on the cars data plate. Some cars cannot even tow 100% of their own weight, where as others can legally tow considerably more.

And you have assumed that MTPLM, is a weight its not: its a limit. The car is not interested in the weight limit of a trailer, its only interested in the actual weight its pulling. The threshold does not use the MTPLM in regards the vehicles loaded capability.

I for example have a box trailer with a 2600kg MTPLM but its unladen mass is only 600kg, I towed it partly loaded with a car that is rated for just 1700kg.

Driving licences are differnt and they do use weight limits to define classes of vehicle, but this should not be a concern to you becasue you seem to be well within the restrictions and besides which those restrictions will be lifted in the near future.