A tongue in cheek advantage of increasing the 85% to 90% or more !!!.

[TheTravellingRooster]

Hi to you all out there. For those that are not to clever with figures and get headaches;please accept my advanced apologies.
There is a move afoot by the caravan manufacturers & the supporting trade bodies to increase the Newbie/Novice 85% guideline to 90% or more,I believe that it is a bonkers idea.By increasing the figure it allows and condones the making of heavier and heavier caravans when cars/tow-vehicles in general are getting lighter & lighter.
That said, there is one very constructive BIG BUT. The kerbweight of the tow-vehicle is the foremost consideration when choosing a caravan (not the maximum tow-weight),the 85% is based upon this figure (when you can establish correctly what it is).
If the caravan manufacturers can make pleas for massaging the figures the figures, then why not the car manufacturers doing the same.
If you take a car at kerbweight (EU Directive 95/48/EC) at 1638kgs (my 1997 Volvo T5 CD Auto) then increase the 90% full tank to 100% full then add a Tow-Bar(the car won't tow with out one)22kgs the weight then becomes circa 1665kgs.At 1638kgs the 85% figure is 1392kgs & 90% it becomes 1474kgs. The newly created definition as per my proposal ie:- EU Directive 95/48/2001/EC sub section strictly tow-cars, would make a massive difference in the already illustrated figures. They would then read as 1665kgs @ 85% 1415kgs or 1665kgs @90% 1498kgs. The 85% goes up from 1392kgs to 1415kgs,not a lot,granted.The 85% of kerbweight could still stand and everyone is happy,in the short term.

 

[mcghee]

your post proves that you can massage the figures any way you want. your outfit is either safe and legal or it's not.

 

[TheTravellingRooster]

This is not an attempt by me to massage any figures for my benefit. My outfits are always legal & safe. It was put up to highlight the reason why the caravan manufacturers are in support of it,and it would appear that there are a number of others with interests in the caravanning reading material departments that are in favour of promoting it. By increasing the 85% figure to 90% or as one party have suggested even to as high as 95% it would mean that caravan manufacturers could add more toys. More toys = more profit. With the figures then getting further apart than they are at present the car manufacturers need a reason to close the gap,that could be done by an artificial increase to kerbweight as per my theoretical new EU Directive. This would actually serve to give our MEP's something to get their teeth into and hopefully not loose them by biting to hard on the bit.

 

[mcghee]

I'm not suggesting you're trying to manipulate the figures for your own benefit. I appreciate your post is only having a bit of fun at how the numbers can be fiddled. I'm only pointing out, like yourself, that figures can be made to read almost any way you like.

However you play the numbers game, whether you can make a theoretical match of 80% or 85% or 90%, the car weighs what it weighs and so does the 'van. You'll either have a solid, safe outfit or you wont and no amount of figure juggling will alter that.

I think it's time this magical, mystical 85% "rule" was abolished in favour of something with a bit more substance.

 

[TheTravellingRooster]

Hi mcghee. Yes it was a bit of fun,but with a serious undertone. The caravan manufacturers have for a long time been telling us that caravans have got heavier because of what we demand in them. It has yet to be proven,but dentist might have a psychosomatic hypnotic skill to make are teeth ache like hell after a trigger word is uttered back home.,especially during slow times of the year.
The truth of the matter is that more toys make more money or make up for trimmed profits during leaner times.Stick a bag of sweeties in front of a child and it's a fair bet that mummy will pick up the bill.
Why therefore can this not be adopted by the motor industry?. By adding on the weights of all of the necessary items to turn an ordinary car into a tow-car it would 'up the anti' and make the tow-car artificially heavier.If you don't want to tow a caravan or trailer it doesn't matter,the car stays at the original Ex-Factory definition/spec. The weight of a tow-bar & its relevant bits is circa 22kgs,this at 85% is just short of 19kgs. The differences in my first illustration could be for a Newbie/Beginner the difference between being kidded that he/she needs a Chelsea Tractor and not parting with a perfectly capable Estate Car.
The more experience caravanner's' will make their choices based on knowledge & experience.
The issue of figure fiddling came into play with EU Directive 95/48/EC which includes a 68kg driver,fuel & a luggage allowance.
Prior to that it was dead simple,kerbside weight was Ex Factory & ready to go but needed fuel & a pilot.
If you take my Volvo at old money and deduct the fiddled figure total of 125kgs that would put it in doubt of pulling an old school Silver Cross Coach-Built Pram with two kids on board & all of the clap-trap needed. I believe that it was initiated in 1995 by Europe because of caravans getting heavier by the year. Cars were getting lighter,yes even back then. What is the answer ?,massage the figures. After all,a car cannot pull a caravan without a driver,oh, and add some fuel and a box of butties for the journey.He-Presto the car is now redefined as being compliant with EU Directive 95/48/EC.

 

[Philspadders]

The truth of the matter is that more toys make more money or make up for trimmed profits during leaner times.
The Automotive sector have been at it for years, facelifting models every 4 to 5 years(the product lifecylce of a car is 4 to 5 years), adding bit of chrome trim or a few extra lights, adding gimmicks. And it works.
Ford and Vauxhall were brilliant at it.
Take the Escort Ghia - a bit of velour upholstery , a radio.cassette player, and a badge . You could pay £800 more for the ghia than the next level down , but still get the same comfort and performance.
The caravan sector is just the same. When you go looking for a new caravan would you choose one with a stereo and large fridge or one with no stereo and a small fridge? For an extra £200 to £300 you can get a stereo thats only worth £20 and larger fridge( perhaps £60.0 more than a small one) Caravans have got heavier because generally we like talking as much of our home with us as possible.
I doubt many caravaners would now buy a new van if it did not have a fridge, a shower , hot water, heating, wash room and a tv ariel and EHU.
But go back 30 years and the standard caravan had a foot pump for water, not EHU, gas mantle lamps, gas cylinders on the outside, glass windows,no shower or hot water, ccertainly no loo for those late nigh emergencies. Ask yourself, would you go back to that , as the van would e very light.

 

[TheTravellingRooster]

Hi again to you all. Whilst I cannot disagree with the comments/observations of Philspadders,I indeed made these very same points some time ago. The real issue of vans becoming heavier and heavier is not just about more toys. It is to do with certain manufacturers making them longer,wider and taller as well (often without a larger chassis) after all the chassis forms the basis of a See-Saw and with judicious balancing etc longer bodies can be planted on chassis to a point.
I believe that a lot is to do with the material weights that are use. Not all lightweight is inadequate. When you look at the offerings from Lunar they really have and still do make very lightweight versions of everyone else's excuses for making vans heavier ;Van for Van comparatives.
With the motor Industry making vehicles lighter and lighter the reasons for buying Chelsea Tractors are making more sense of non sense. The next thing will be Designer & Celebrity Interference on Massey Ferguson and David Brown Tractors,eat your heart out Lawrence & Victoria. Now you could really go from work to play with one of these as a Dual Functionality Excuse.
I wonder how long it will be before we see Carbon Fibre show itself into the caravan industry?, for item such as doors,draw fronts,bed box fascias,locker doors etc. After all,if it can stand the rigours of The Tour de France and The Paris Roubaix then caravan panel components are surely easy-peasy.

 

[ProfJohnL]

Tongue in cheek or not, this is an important matter, and as many of you will know I have strong and what maybe considered untraditional views on the subject.
The current 85% recommendation by the industry is very much a compromise. When it was suggested, it was a best guess, because there was inadequate technical information available about the cars we were using at the time. Its introduction was I am sure pushed on the basis of what is safe, however it has assumed a bigger role than that and for some caravanners it is a holy grail to be achieved even at the cost of ignoring other important towing factors, and it has no legal basis!
Part of the issue is why 85%! Why not 67, 75 or 90%? Or even 100%. What is a safe ratio? I happen to think that setting the maximum towed weight referenced to an impossible to achieve kerbweight is illogical. And the same argument can be applied to any system that does not take into account the abilities of the tow car as proven in the cars Type approval documentation.
The caravan manufacture may have their commercial reasons for wanting the recommendation to be changed, but in fact there is nothing stopping them from ignoring the recommendation now.

 

[Steve L]

I tend to agree with John on this subject.
For many years 85% of the tow car's kerb weight has been bandied about as a "safe tow limit", as if it was a guarantee.

So if that is a guarrantee of a safe outfit, an articulated lorry tractor unit would have to weigh 42.5 ton if it towed the max weight trailer giving a current artic a 44 ton capability we see today. Or your average Landrover towing a 3500Kg trailer which it is rated to tow would have to weigh 2975 Kgs kerb weight.

Car manufacturers of both cars and 4X4's go through a very tough type approval process to determine a safe tow capacity for each vehicle. They don't just pluck figures out of the air.

My Rover 75 Tourer has a gross train weight of 3750Kgs, which is the max weight of car + passengers + fuel + trailer. It also has a gross weight for the car of 2150Kgs which is Car + passengers + fuel. So 3750 -2150 = 1600Kgs trailer weight. Quite simple and straight forward information on a VIN plate that VOSA inspectors read and use when weighing you during a roadside vehicle check.

The only true key to safe towing is loading your caravan correctly to give a nose weight on the hitch. Now this is where I contradict myself, because I have found throughout my 28 years of towing trailers, that 75Kgs seems to be an ideal nose weight. From a legal point of view, you must use the lower of the figure's quoted for nose weight of the caravan and the hitch loading weight stated by the towbar manufacturer as being your maximum noseweight.

I arrived at 75Kgs for this as, if I loaded lighter I got the feeling that the caravan controlled the car's stability, and if I went for more than 75Kgs, the hitchhead seemed to stick or drag in it's housing and as such it delayed putting the trailer brakes on.

Practical caravan has a very good loading guide in the mag. Using that and weighing your hitch with a guage or bathroom scales under the jockey wheel will give you your ideal loading plan. Now if you show everyone in your family who loads the van you should have a good idea of how to load for stability of towing. But even after doing that, I would still advocate checking the hitch weight prior to every journey. You'd be suprised how much that pack of lager's alters your stability without even drinking them

 

[ProfJohnL]

Hello Steve,
This is turn up for the books both of us actually agreeing! However I mustn’t disappoint our avid followers;

You have taken a small liberty with my posting, which was about caravans – not HGV tractor units, It is the Caravan industry that tries to imposes the 85% recommendation, and it relates only to UK caravans. Of note no other country applies a similar restriction, so the UK really is out on a limb.
Also I think you have got your maths wrong in your examples, the 85% relates to the weight of the tow vehicle, so the LR with a tow limit of 3500Kg would need to be 4375Kg, and the 38T artic would need a tractor of 47T! – but neither of these are real scenarios.
There is also a very important difference between caravans and HGV artic units. Because the fifth wheel (tow hitch) of an artic sits within the wheel base of the tractor unit, a significant part of the trailers load is transferred to all the wheels of the tractor unit, This improves the traction and steering grip of the tractor unit. Whereas the tow hitch of a car sits behind the rear wheels and thus outside of the cars wheel base, and the trailers nose load will upset the balance of the cars axles to some extent.
For anyone who wants a simple demonstration of the difference, if you press down on the centre of a saucer, the saucer grips the table harder. This is the HGV tractor unit model, the car is like pressing down the edge of the saucer, which tends to make it less stable.

 

[TheTravellingRooster]

Hi to you all out there. When I started this post topic off it was as titled a 'Tongue in Cheek' stab at both the caravan manufacturers & the vehicle manufacturers. In so-much as what is good for the goose etc. Massaging figures is associated with ulterior motive,which is often a Political Ploy but it can have knock-on beneficial effects.The caravan manufacturers are not the ones that have set the recommended figure of 85%,they build what they want,then leave it to the Chelsea Tractor Manufacturers to benefit with higher sales.
To pick up on some of Prof John L's comments. If data was available it might well show that there was/has been/is a trend that the recorded accidents/incidents with vehicles towing caravans was largely associated with seasoned/"experts" in the caravanning world;not the Newbie/Beginner caravanner.When I say seasoned/"experts" I really mean the; I've been towing all of ten years brigade,but actually only for one annual trip of 50miles each way and have a vehicle that the manufacturers say can tow 2500kgs!!! but it only weighs 1800kgs!!!,oh well they should know,they made it.
Kerbweights are NOT IMPOSSIBLE to achieve,difficult-yes,airy-fairy-definitely.My own experiences with Volvo Cars UK ,Towsafe and several caravan dealers could fill six sides of A4 easily.
The definition of kerbweight as defined in the Blue Pages of Practical Caravan Magazine is very specific,the only iffy bit is to establish exactly 90% of your fuel tank,that is achievable within a litre or so (less than 2kgs in real terms). My 1997 Volvo V70 T5 CD Auto has a full tank capacity of 70ltres,the difference between 90% & full is 7litres. That weighs 5.128kgs. Fill up the tank to brimming,forget the 7kgs luggage allowance and add in the 68kg driver (me). My car on a VOSA Dynamic Axle Weighbridge (accurate to 0.5%,the most accurate in the world) is 1638 kgs.
If I sold my car to a Newbie/Beginner caravanner the 85% recommendation would be 1392kgs.
If that same Newbie/Beginner went off the Towsafe Data with the variations, all for the same vehicle then they would end up buying a Chelsea Tractor!!.They had/have my car at 1392kgs!! the 85% recommendation would then be 1183kgs !!!!!!!!!!!!!!!!!!!!!??.
Volvo have the car rated as (Maximum mass of trailer(braked)1600kg on the EEC Certificate of Conformity )a Maximum Permitted Towing Weight of 1600kgs.This figure is 15% over the Towsafe published kerbweight for MY car.It is however 2.5% under what I now know is my kerbweight.
Is there little wonder why those thinking of becoming Newbies/Beginner Caravanner's support flying away for their holidays and taking their money out of the UK economy ?.

 

[ProfJohnL]

Hi Rooster
I think you last post gives an admiral demonstration of why trying to link a recommended trailer mass to a specific percentage of a cars kerbweight is invariably going to lead to errors, and that is just one of the reasons that I dislike the “85%” figure.
Whilst I hate with a vengeance the use of “85%” because it misdirects attention away from other important factors, I do concede that allowing caravan to use the entire towing capacity of car may not be a sensible action. My reason for stating this is that I consider caravans to be an extreme trailer, they are bulky, and due to their size they can be affected by other forces that physically smaller trailers may just shrug off.
So some method of de-rating the towing capacity of cars for caravans may be a valid proposition.

 

[mcghee]

So maybe the towing limit for trailers over a specified height should be a percentage of the vehicles towing limit. Or maybe a percentage of the vehicles actual weight in use, which would be more realistic.

I don't know who arrived at the figure of 85% rather than 84 or 86, i think it's just a number that sounded good to someone at the time.

But there's no denying that telling a new caravanner to choose a caravan weighing less than 85% of his or her car's theoretical, mystical, could-be-might-be, kerbweight only serves to create an unnecessary problem.

 

[JonnyG]

"the 85% rule",Always found this a really strange thing for anyone to come up with as a generalization.Especially as cars vary so much from each other,and when you think how cars have advanced since this rule was introduced and indeed caravans too,then it makes even less sense.

 

[TheTravellingRooster]

Hi Prof John L. Yes,the other forces are many and each is not the same as the time before. The one that is the most unpredictable of all has got to be the variable strength cross wind and especially when made more unruly be a massive Articulated Deathmobile passing to close for comfort,even though steps have been taken to allow for the Titanic Sinking Bow-wave. Having towed both single and twin axle caravans I would not go back to single axle by choice,even allowing for the fact that twin axle are longer they are far more stable in the worst of the likely battles to stay on course.

 

[JonnyG]

"I would not go back to single axle by choice,even allowing for the fact that twin axle are longer they are far more stable in the worst of the likely battles to stay on course."

Just wondering how true that is? Is it a generalisation, so as to say any twin axles is more stable than anything offered on a single axle?
If it is true,and that seems to be the general opinion, then they must be pretty stable even in cross winds or indeed when battling against artics, if my single axle burstner is anything to go by, with its longer A frame design that seems to have kept me safe for 4 years, in the worst of cross winds or indeed over taking manoeuvres, even though the caravan is 7.5 metres in shipping length.

 

[ProfAlGoogle]

Here we go again twin v single (yawn) please lets try and keep it on topic, the latter having been done to death so many times before.

Allan & Gill.

 

[Surfer]

With most cars manufacturered these days, the maximum braked towing limit is way below the kerbweight of the car so all these percentage guidelines are immediately trashed. As it is only a guideline it can be increased or decreased as per an individual's preference as long as it is within the car's maximum towing limit to comply with the law.

Also don't forget that every day many people are towing well in excess of the kerbweight of their vehicle legally and this is excluding HGVs etc.

 

[ProfJohnL]

Hi Mcghee

Yes, that’s the sort of thing that might work. If some simple but repeatable measurements and data could be put into a spreadsheet to help ‘model’ both the car and the caravan, this might be able to produce some guidance outputs.

I have seen a copy of the summary report that Bath University did for Bailey, which makes for quite interesting reading.

Apparently several attempts have been made to produce mathematical models of towing outfits, and they do become quite complex, but they were looking for fine detail where as I feel there is scope for a more generic model that might be significantly more valuable than the simple towing ratio that is currently derived.

 

[JonnyG]

Here we go again twin v single (yawn) please lets try and keep it on topic, the latter having been done to death so many times before.

Allan & Gill.

Has indeed has the 85% rule topic itself! So what's so different? maybe you need a little more sleep so to stop you from yawning!
Personally if somebody can post "they would never tow a single axles caravan again"Yawn", why is it,that those that tow a single axle caravan,without any problems cannot say so! You are welcome to give your opinion, but who the hell are you to tell me what I can post as my opinion.

 

[ProfAlGoogle]

Ouch,

Jonny G sorry if I offended you that was not my intention (Parksy I'm being bullied

) but it seems when we go down the twin v single route we seem to loose the jist of the original post as we have done so in the past on so many occasions, and in my opinion this is a really interesting post.
for what it is worth I have towed caravans for well over forty years, twins and singles, and the main criteria has always been the actual van layout, from having a young family where we required bunk beds, to now where our needs have changed and we have a fixed bed, for me axles have never played a part in my choice of vans, but I do appreciate that other people will have different views to me when making there choice of caravan.
Allan & Gill.

 

[Parksy]

I've only just found my permed scouse wig and false moustache.............. Ok, calm down, calm down!

The manufacturers might be attempting to move the goalposts on the 85% guideline because the width of tourer that can be towed was increased last April to 2.55 metres. I haven't seen any new designs with the wider bodies from UK manufacturers yet but they are sure to appear sooner or later. We changed from a single axle caravan to a twin axle model but the t/a still has to be loaded correctly to remain stable on the road. Our s/a Abbey 495 wasn't unstable and neither is our t/a Abbey 620 but my driving style hasn't altered. If I started whizzing past lorries or coaches going downhill on a windy day it wouldn't matter how many axles the caravan had, it would still finish upside down

 

[Parksy]

Ouch,Jonny G sorry if I offended you that was not my intention (Parksy I'm being bullied )

I've only just found my permed scouse wig and false moustache.............. Ok, calm down, calm down!

The manufacturers might be attempting to move the goalposts on the 85% guideline because the width of tourer that can be towed was increased last April to 2.55 metres. I haven't seen any new designs with the wider bodies from UK manufacturers yet but they are sure to appear sooner or later. We changed from a single axle caravan to a twin axle model but the t/a still has to be loaded correctly to remain stable on the road. Our s/a Abbey 495 wasn't unstable and neither is our t/a Abbey 620 but my driving style hasn't altered. If I started whizzing past lorries or coaches going downhill on a windy day it wouldn't matter how many axles the caravan had, it would still finish upside down

 

[ProfAlGoogle]

Could not agree with you more Parksy, we used to have an Elddis super storm t/a, loading correctly was an absolute must, otherwise it towed like a total pig. Now look what you have done, Ive gone off topic..............................................................

Allan & Gill.

 

[Steve L]

As most of you know the 85% (not a rule never has been. Just a guide drawn up by some brainstormer) topic has clouded and confused practically every caravanner new or old.

While I still concur with John, I used the Articulated lorry example just to show how much of a load is put behind these vehicles. We regularly hear of jacknifed lorries in the winter and that is mostly down to driver error, but also it is down to the much heavier trailer pushing the tractor unit.

A single axle caravan can be almost as stable as a twin axle van if it is loaded correctly, but by the same token a badly loaded twin axle van can be just as likely to sway and jacknife.

That is why I have no real approval of any mythical percentage as being any form of safe towing statement.

That is also why I'm very much in favor of car manufacturers being very specific on their tow capacity statement. Having owned Renaults in the past I can honestly say their towing information in their hand book for the car is nothing short of diabolically difficult to comprehend. But if like me you are used to driving lorries and can understand Gross train, gross vehicle weights and axle load weights, and can also read a vin plate. You can workout what the max trailer weight can be.

So rather than massage percentages, i would rather see black and white "your car will tow xyz Kgs of unbraked trailer or xyz Kgs of braked trailer, clearly stamped on the VIN plate and also on a plate clearly visable on the towbar. But I know that my rocking horse would win the grand national before that would see the light of day, let alone become legislation.