Can we really believe (AND RELY ON) what we read in Practical Caravan Magazine ?

ProfAlGoogle · Jan 25, 2013

But of course

Surfer · Jan 26, 2013

Prof John L said:
This thread demonstrates one of the reasons why I suggest the 85% guidance is so imprecise and flawed. If the main key variable (kerbweight) cannot be consistently ascertained, then the output of any calculations based on it will also be flawed. - But in the absence of any other agreed method it is still better than nothing.

When the 85% guideline was thought up, wasn't one of the reasons because cars in those days had a much lower bhp even though they were heavier? I think the UK must be the only country with this guideline?

ProfAlGoogle · Jan 26, 2013

I can well remember when I started out with my 1st caravan purchased from selston caravans in Nott's, in the early 70s, there was posters in the vans with the information : 4 berth towable by a 1600cc car etc.
In our case we purchased a sprite musketeer, vintage late 50s, glass windows, steel chassis, pull down double bed in the rear complete with mattress, and a 2" coupling, not a clue what it weighed but it was a heavy old beast, and displayed in the window "suitable for a 1600cc car" at the time I had a Hilman super minx with a 1700cc engine, it pulled it just.......................................lol

ProfJohnL · Jan 26, 2013

Its not clear when the guidelines were introduced, nor the reason why, or the basis of the actual figure, but back in the 1970's there were few details published of the vehicles capabilities regards towing, so a guidance was a sensible approach. It has apparently been revised at some point, but the factual and technical basis of the recommendation has never been published.

What has changed is the EU's type approval system for cars, where there is now repeatable test evidence to support car manufacturers specifications for towing capacity of ideal trailers.

Caravans are not ideal trailers, so it makes sense to apply some sort of handicap which represents the deviation a caravans towing characteristics from the ideal trailer, and then relate that to the car manufactures specified maximum towing limit.

ProfAlGoogle · Jan 26, 2013

Not sure if this has any bearing on the 85% guideline, but back when I had my 1st caravan in 1971 the speed limit for a car towing a caravan was 40mph, I think it was around the late 70s early 80s the speed limit was increased to 50 mph. The criteria for the new limit was that you had to display a 50 sticker to the rear of the caravan and also the weight of the caravan had to be displayed on the drawbar of the caravan and also on the rear of the towing vehicle, if not you were restricted to 40 mph.
you could buy sheets of self adhesive numbers witl sticky black boxes that you put the numbers in to, could it have been that if you we're below 85% of the cars kerweight that you could tow at the new speed limit ??? Any one out there with a better memory than mine, I know I'm correct with the advent of the new 50 mph limit and displaying the weights, but that's when my memory starts to cloud.

NigelHutson · Jan 28, 2013

Prof Al Google said:
Not sure if this has any bearing on the 85% guideline, but back when I had my 1st caravan in 1971 the speed limit for a car towing a caravan was 40mph, I think it was around the late 70s early 80s the speed limit was increased to 50 mph. The criteria for the new limit was that you had to display a 50 sticker to the rear of the caravan and also the weight of the caravan had to be displayed on the drawbar of the caravan and also on the rear of the towing vehicle, if not you were restricted to 40 mph.
you could buy sheets of self adhesive numbers witl sticky black boxes that you put the numbers in to, could it have been that if you we're below 85% of the cars kerweight that you could tow at the new speed limit ??? Any one out there with a better memory than mine, I know I'm correct with the advent of the new 50 mph limit and displaying the weights, but that's when my memory starts to cloud.

Hi Al,
It was the early 70's that the 50mph was introduced. You're quite right in that a 50 sticker had to be put on the rear of the caravan. The gross-weight of the caravan had to be placed "in a conspicuous place" on the caravan, and also the kerbside weight of the towing vehicle "displayed in a conspicuous place" on that. The only real criteria other than the above was that the gross weight of the caravan must not exceed the kerbside weight of the car.
Halcion days when things were simple!

otherclive · Jan 28, 2013

Two things strike me about this discussion, firstly its not always feasible to look at your V5 as it doesn't come along until your new car is delivered. Alright if your buying a used car, but with a new one you'd have to visit a dealer and ask to see a similar spec car to the one you plan to buy and then ask to see its V5. Secondly my caravan owners manual quotes a tolerance of +- 5% on MIRO against the specified figure. That's 50kg either way for each 1000kg of MIRO. so your van could be the light one or the heavy one. But the MTPLM doesn't change so you could have increased or reduced payload. But of course your van MIRO might change by that amount depending on ambient conditions. I don't know wether the more modern vans have this weight tolerance stated or perhaps the newer build materials are less sensitive to humidity/ moisture variations.
I have always done my own research re tow car and van compatibility ever since when I bought our first van and the dealer said that my BX 16 estate would be absolutely fine. He wasn't aware of the BX weight or max tow weight, which were not suitable for the van, but unbeknown to him we had a Mondeo which was compatible!

chenzhen · May 19, 2016

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Can we really believe (AND RELY ON) what we read in Practical Caravan Magazine ?

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