New Tow Car advice?

[Raywood]

I accept that the 85% advice is neither foolproof or perfect. The fact is newcomers need advice and weight ratios are important, without anything better it has to stand. Personally I would like to see some more research on the subject but at the end of the day because different combinations mean results are not consistent and newcomers need advice we have to live with the figure. The Towing Code does include advice on other things like correct loading and nose weights, so the 85% bit should not be read in isolation.

 

[camel]

In view of the fact that the 85% weight ratio recommendation is unknown and unheard of on the Continent but one doesn't see their roads littered with overturned caravans shows that the weight ratio recommendation needs to be put into a realistic perspective.

I think there is a place for the 85% weight ratio, If you are newby to caravanning and don't have a clue you could or might load up your caravan to the extreme and have the caravan heavier than the towing vehicle, so Mr Newby reads about the 85% weight ration and says thats a good idea, I'm afraid not all caravanners or experts in the fundimentials of caravan weights, personally for tha last three years I have been at 97% towing with my 14 plate Qashqai, but now I have a 16 plate 150psi ford Kuga which now brings my towing % well down,

 

[ProfJohnL]

A very nicely put comment Prof, and one which I agree with. Err on the side of caution, drive with caution and load safely but there are so many variables further research would be very useful!

Further research. now there's another chestnut.

There is an often referred to piece of useful work carried out by the University of Bath on behalf of Bailey Caravans in nearby Bristol. The paper defined a number of characteristics that affect the towing behaviour of a caravan behind a car. The work produced a model that was demonstrated at several locations that showed how the load distribution on a trailer can affect the handling of a car and trailer combination. The demonstration was quite dramatic, and I applaud the intention and hopefully it made some of its audience think a little more about how to distribute load in their caravan.

The demo was very dramatic, and it did help to explain the principal of the point that was being made, but what it did not do was to fairly represent a real car and caravan. There were some significant deviations from the real car and caravan actually used in the project.

The project did come to some cogent conclusions, but the evidence and results only came from one car and one caravan, so the specific results and conclusions cannot be assumed to be equally applicable to all outfits. (that's why i'm not quoting the results)

That demonstrates the point of this comment. To generate enough practical evidence to be able to produce a universal stability formula would be a never ending project, which would continue to grow in complexity as every new car or caravan was produced.

I actually discussed the idea of this with a couple of ex Uni' of Bath Masters of automotive engineering, and there is passion to do something, but no funding to even start the ground work to explore the scope of the project.

As Lutz has pointed out above and on a number of previous threads, the UK is as far as I know unique in having this type of industry advice, Perhaps it would make more sense to study how other countries do manage to keep stability failure so low.

One suggestion concludes its the practice on continental caravans to have longer A frames. But also its more common for caravans to be fitted with suspension dampers.....and the list goes on.

 

[ProfJohnL]

I think there is a place for the 85% weight ratio, If you are newby to caravanning and don't have a clue you could or might load up your caravan to the extreme and have the caravan heavier than the towing vehicle, so Mr Newby reads about the 85% weight ration and says thats a good idea, I'm afraid not all caravanners or experts in the fundimentials of caravan weights, personally for tha last three years I have been at 97% towing with my 14 plate Qashqai, but now I have a 16 plate 150psi ford Kuga which now brings my towing % well down,

It seems strange that in continental Europe no other country has need of the UK's industry advice. There must be in experienced caravanners there too, so how do they start on this journey of discovery without the advice that is so dogishly followed in the UK?

Any continental caravanners wish to tell us how they manage?

 

[camel]

I've towed with a long A frame when I had a Lunar Chateau and a far better it was than a bog standard UK type A frame,

 

[Raywood]

Perhaps our caravan builders should be looking at longer A frames as this should help. Presumably we use more ferries than most other nations and are more aware of their costs, this might make us inclined to go for a shorter overall length model.
I acc3ep-t that other countries may have no similar figure for newcomers but that may be to their disadvantage. What we need is for the two clubs to fund more research so that we can get better answers.

 

[otherclive]

Perhaps our caravan builders should be looking at longer A frames as this should help. Presumably we use more ferries than most other nations and are more aware of their costs, this might make us inclined to go for a shorter overall length model.
I acc3ep-t that other countries may have no similar figure for newcomers but that may be to their disadvantage. What we need is for the two clubs to fund more research so that we can get better answers.

I seem to recall that at one time German vans had two speed limits dependant on certain criteria being met. I think that there was a lower max speed limit of 80 kph but a higher speed limit of 100 kph if the van met certain criteria such as dampers being fitted and were TUV involved in checking the van. Perhaps Lutz will advise.
France had two limits for many years. These were based on the plated weight of the outfit being 3500 kg or below, or exceeding 3500 kg. As they were plated weights the actual loaded weight of the outfit was not relevant to the speed limit legislation. So you could envisage a lighter outfit whose plated weight exceeded 3500 kg being overtaken by an outfit whose plated weight was less than 3500 kg but car and caravan loaded to the maximum.

Im not in favour of my subscriptions to the Clubs being used to fund research as Prof says its such a complex issue that I don’t even think any new information would come about. The factors that affect stability are well known and weight ratio is only one of them. Like Germany our roads are hardly littered with upended caravans. From dash cam footage and online videos of accidents I’m not convinced that the outfit that had the accident was mismatched against the general kerb weight to MTPLM guidance of 85%.

 

[ProfJohnL]

I seem to recall that at one time German vans had two speed limits dependant on certain criteria being met. I think that there was a lower max speed limit of 80 kph but a higher speed limit of 100 kph if the van met certain criteria such as dampers being fitted and were TUV involved in checking the van. Perhaps Lutz will advise.
France had two limits for many years. These were based on the plated weight of the outfit being 3500 kg or below, or exceeding 3500 kg. As they were plated weights the actual loaded weight of the outfit was not relevant to the speed limit legislation. So you could envisage a lighter outfit whose plated weight exceeded 3500 kg being overtaken by an outfit whose plated weight was less than 3500 kg but car and caravan loaded to the maximum.

Im not in favour of my subscriptions to the Clubs being used to fund research as Prof says its such a complex issue that I don’t even think any new information would come about. The factors that affect stability are well known and weight ratio is only one of them. Like Germany our roads are hardly littered with upended caravans. From dash cam footage and online videos of accidents I’m not convinced that the outfit that had the accident was mismatched against the general kerb weight to MTPLM guidance of 85%.

Thanks Clive,

The majority of the factors involved with instability are known, but quantifying them, and working out their interrelationships is where the costs would rise. Decisions about how fast should you test at, and what road surface, what direction of wind, steady or gusting and how does the driver react or influence the events..........Rain, puddles tram lines ...... dare I mention nose load or car transporters?

I'm certain the majority of instability occurrences do not end with disaster, most will probably be just a wobble and the driver is able to bring it back under enough control to live again, These incidents won't show up in Ray's statistics.

I do think if properly considered research were undertaken, we could come up with a more effective outfit matching process, but it is the research that would be costly and time consuming.

 

[camel]

I presume when Bailey did their scientific caravan towing tests that Alko ATC control did not exist , I suppose the system will encourage bad loading of caravans with some people,

 

[Scorpy]

With a caravan of that weight I suggest you forget the Sportage and look at a KIa Sorento. Mine is same ball park as you (perhaps a little heavier) but never have a problem with the Sorento. Don't think I'd like the idea of a van of that weight pushing me about downhill in a Sportage!

 

[Parksy]

Happy New Year to all!

Unfortunately i have had to part ways with my current tow car which was a 2005 Ranger Rover. I am now in the market for a new tow car. I have a 2017 Bailey Cordoba, twin axle which fully laden weighs 1,750kg. I have been looking at the 2013 - 2015 Kia Sportage, CRDi 181BHP and also the Ford Kuga 180PS, similar age both of which are automatics and from the previous posts have been discussed in length, but that was for lighter vans. They both have a tow limit of 2,100kg - 2,200kg. I am curious and wondered if anyone has towed a twin axle with either of these cars and welcome feedback/advice?

Cheers

Rob.

This topic has departed far, far away from the OP and has defaulted to the usual forum hobby horse about the 85% towcar / caravan ratio recommended by both major clubs and other organisations for the guidance of relatively inexperienced caravanners.
Discussion about the 85% recommendation have taken place on this forum since the forum first began, here's one picked at random from 2016 and there's nothing new to add that hasn't already been aired here.
It's unfair to hijack queries posted by members asking for simple advice about the merits or otherwise of various towing vehicles.
If members wish to discuss the 85% recommendation ad nauseum please have the courtesy to do so on a thread that you have opened for that purpose, it's rude to hijack other peoples threads.

 

[camel]

This topic has departed far, far away from the OP and has defaulted to the usual forum hobby horse about the 85% towcar / caravan ratio recommended by both major clubs and other organisations for the guidance of relatively inexperienced caravanners.
Discussion about the 85% recommendation have taken place on this forum since the forum first began, here's one picked at random from 2016 and there's nothing new to add that hasn't already been aired here.
It's unfair to hijack queries posted by members asking for simple advice about the merits or otherwise of various towing vehicles.
If members wish to discuss the 85% recommendation ad nauseum please have the courtesy to do so on a thread that you have opened for that purpose, it's rude to hijack other peoples threads.

I've had my Ford Kuga a couple of weeks now and I have seen three kerbside weights for it so one of the first things I did was get to a weighbridge for the proper weight,

 

[Parksy]

I've had my Ford Kuga a couple of weeks now and I have seen three kerbside weights for it so one of the first things I did was get to a weighbridge for the proper weight,

I'm very pleased to learn that you did Camel, but the OP hadn't even decided what make or model he wanted to look at, so he would have had no chance of taking it to a weighbridge.
Nobody's fault really, but I know for a certain fact that many forum members are put off asking a fairly simple straightforward question because all too often their original question is buried beneath masses of off topic technical debate about things that are discussed ad infinitum on this forum.
I'm not trying to stifle discussion, I'm simply asking members to have the good manners to open a seperate thread rather than hijacking someone elses thread.

 

[ProfJohnL]

I'm very pleased to learn that you did Camel, but the OP hadn't even decided what make or model he wanted to look at, so he would have had no chance of taking it to a weighbridge.
Nobody's fault really, but I know for a certain fact that many forum members are put off asking a fairly simple straightforward question because all too often their original question is buried beneath masses of off topic technical debate about things that are discussed ad infinitum on this forum.
I'm not trying to stifle discussion, I'm simply asking members to have the good manners to open a seperate thread rather than hijacking someone elses thread.

Hello Parksy.

I appreciate the point you make. Unfortunately debates about the suitability of tow cars for towing a particular caravan invariably come down to references about using the industry advice. After all that is so often held up as the arbiter for a good match.

In this case the identified car has certain attributes which suggest the use of the industry advice may under rate it as a tow vehicle. That opens up the debate about the efficacy of the advice, and so its goes on. It has a relevance to the thread, unlike the comments about LEZ's in another recent thread.

If necessary I will open a new thread.

 

[Parksy]

Hello Parksy.

I appreciate the point you make. Unfortunately debates about the suitability of tow cars for towing a particular caravan invariably come down to references about using the industry advice. After all that is so often held up as the arbiter for a good match.

In this case the identified car has certain attributes which suggest the use of the industry advice may under rate it as a tow vehicle. That opens up the debate about the efficacy of the advice, and so its goes on. It has a relevance to the thread, unlike the comments about LEZ's in another recent thread.

If necessary I will open a new thread.

The OP stated that he is getting rid of his previous towcar, a 2005 Range Rover which towed his 2017 Bailey caravan.
This would suggest that the OP isn't a novice when it comes to towing a caravan.
As I'm sure that you're aware Prof, the 85% recommendation is primarily aimed at those unused to towing touring caravans, an experienced caravanner will be able to decide for themselves whether to follow the 85% advice or not, they don't need a lengthy debate about the relevancy of this advice or how the 85% figure may have been arrived at.
There is plenty of scope for discussion about issues surrounding the 85% advice, but the original query has been swamped in this case by another lengthy discussion about an issue that the OP didn't ask about and probably doesn't need.

 

[Gafferbill]

....... if the OP likes the Kia Sportage as he has stated and he is looking to replace a Range Rover, then surely he should be looking at a Sorento which has been proven by many to be suitable for towing a 1750 kgs caravan.

PS........I agree with the previous post by Scorpy.

 

[Lutz]

To clarify the position in Germany:

The regular speed limit for any towed outfit is 80km/h. However, one can apply for a concession to tow at 100km/h subject to fulfilment of the following conditions:

1. The towing vehicle must have a GVW of no more than 3500kg.
2. It must be equipped with an ABS braking system
3. The trailer must be approved for towing at 100km/h
4. The tyres of the trailer must have an L speed rating or better
5. The tyres of the trailer must be less than 6 years old
6. If the weight ratio exceeds 30% the trailer must be equipped with dampers. In the case of a caravan fitted with brakes and dampers, the weight ratio must not exceed 80% unless it is also equipped with a passive stabiliser OR the trailer or the towing vehicle with an active electronic stabiliser system, in which case the weight ratio must not exceed 100%. For braked trailers other than caravans these limits are 110% and 120% respectively.

One would assume that with such a differentiation, there must have been some thorough investigation conducted prior to their definition.

 

[otherclive]

To clarify the position in Germany:

The regular speed limit for any towed outfit is 80km/h. However, one can apply for a concession to tow at 100km/h subject to fulfilment of the following conditions:

1. The towing vehicle must have a GVW of no more than 3500kg.
2. It must be equipped with an ABS braking system
3. The trailer must be approved for towing at 100km/h
4. The tyres of the trailer must have an L speed rating or better
5. The tyres of the trailer must be less than 6 years old
6. If the weight ratio exceeds 30% the trailer must be equipped with dampers. In the case of a caravan fitted with brakes and dampers, the weight ratio must not exceed 80% unless it is also equipped with a passive stabiliser OR the trailer or the towing vehicle with an active electronic stabiliser system, in which case the weight ratio must not exceed 100%. For braked trailers other than caravans these limits are 110% and 120% respectively.

One would assume that with such a differentiation, there must have been some thorough investigation conducted prior to their definition.

Thank you Lutz. A defined approach but one which many newer U.K. caravans probably meet as all cars are likely to have ABS and stabilisers and ATC are now widely fitted.

 

[JTQ]

Thank you Lutz. A defined approach but one which many newer U.K. caravans probably meet as all cars are likely to have ABS and stabilisers and ATC are now widely fitted.

Are UK caravans now generally factory fitted with suspension dampers, and ATC?

We have been out of the loop in purchasing for over a decade, but back then both were uncommon standard fits.
And I should add IMO both are "must haves" and their omission reflected poorly, in my view of the builders of the time.

 

[ProfJohnL]

Are UK caravans now generally factory fitted with suspension dampers, and ATC?

We have been out of the loop in purchasing for over a decade, but back then both were uncommon standard fits.
And I should add IMO both are "must haves" and their omission reflected poorly, in my view of the builders of the time.

In the UK Dampers and ATC are usually offered as optional extras. I cant comment on the what is normal elswhere.

 

[otherclive]

Are UK caravans now generally factory fitted with suspension dampers, and ATC?

We have been out of the loop in purchasing for over a decade, but back then both were uncommon standard fits.
And I should add IMO both are "must haves" and their omission reflected poorly, in my view of the builders of the time.

A lot are and increasingly new buyers opt for ATC as an option.

 

[Lutz]

Thank you Lutz. A defined approach but one which many newer U.K. caravans probably meet as all cars are likely to have ABS and stabilisers and ATC are now widely fitted.

My response was directed more in the direction of those who were asking whether there is any technical evidence to support the 85% weight ratio figure. The manner in which the German regulations are defined would suggest that some differentiation is required, especially regarding the need for dampers. Without them one would be limited to a 30% weight ratio, so the lawmakers must have considered them as an important fitment.

 

[camel]

In view of the fact that the 85% weight ratio recommendation is unknown and unheard of on the Continent but one doesn't see their roads littered with overturned caravans shows that the weight ratio recommendation needs to be put into a realistic perspective.

To make things simpler when a caravan comes off the probuction line it is put on a weigh bridge and given a manyfacturers plate saying what the tare weight of the caravan is, you then take the maximum axle weght take off the tare weightfrom the axle plated weight, and that gives you the pay load you can load in the caravan add all three wieghts together to give you a gross weight and if your vehicle is capable of towing according to the max towing weight gi en in your handbook, away you go, if you are legal,

 

[Lutz]

To make things simpler when a caravan comes off the probuction line it is put on a weigh bridge and given a manyfacturers plate saying what the tare weight of the caravan is, you then take the maximum axle weght take off the tare weightfrom the axle plated weight, and that gives you the pay load you can load in the caravan add all three wieghts together to give you a gross weight and if your vehicle is capable of towing according to the max towing weight gi en in your handbook, away you go, if you are legal,

If only things were that simple. The MIRO figure shown on the label by the door does not necessarily represent the acutal weight of the particular caravan in question. Contrary to what you say, caravans are not weighed as they come off the line. One caravan that is declared as representative of that model and without any factory fitted optional extras is weighed for type approval purposes and that is declared as the MIRO, which as such, is a generic figure for all caravans of that model and applies to all caravans covered under the same type approval number. That is how MIRO is defined in the regulations. The actual unladen weight could well be higher. It could result in quite a considerable variance from the figure displayed on the label.
Secondly, you cannot compare the towing weight of the towing vehicle with the overall weight of the caravan. The towed weight is the axle load of the caravan, not its overall weight. Even that is not a matter of legality. What is legally important is that none of the plated weights are exceeded. The towed weight is not a plated figure. What this means is that none of the following may be exceeded:
1. The gross train weight of the whole outfit
2. The GVW of the towing vehicle
3. The MTPLM of the caravan
4. and all the maximum permitted axle loads of both car and caravan.

 

[camel]

If only things were that simple. The MIRO figure shown on the label by the door does not necessarily represent the acutal weight of the particular caravan in question. Contrary to what you say, caravans are not weighed as they come off the line. One caravan that is declared as representative of that model and without any factory fitted optional extras is weighed for type approval purposes and that is declared as the MIRO, which as such, is a generic figure for all caravans of that model and applies to all caravans covered under the same type approval number. That is how MIRO is defined in the regulations. The actual unladen weight could well be higher. It could result in quite a considerable variance from the figure displayed on the label.

This is e avtly what I'm saying they give one weight to a particular model of caravan , this is why I always have a weighbridge ticket for both my vehicle and caravan then I know what I can legally tow and load in my outfit,