Revision to recomended towing limit

[ProfJohnL]

There is a growing debate about the recommended towing ratio.

For several years a number of contributors to this forum have questioned the long-standing recommendation that outfits should conform to an 85% ratio.

Whilst researching another topic, I came across this web page.

http://www.outandaboutlive.co.uk/channel/articleitem.asp?article=317

This is the first time that I have seen any authoritative body openly questioning the CC’s and C&CC now outdated position.

It is refreshing to see that others are now opening their eyes to the developments in automotive technology, rather than doggedly following traditions based on misguided belief that the clubs have a monopoly on the best practice.
It is a real shame that on the same page there is a link to the Towmatch web site, where the traditional myths (85% and never more that 100%) are perpetuated.

 

[Lutz]

I would question whether the relatively small difference between 85% and 90% is even noticeable by anyone. While the magazine has recognised the need for a critical reappraisal of the recommendation, I doubt whether their suggestion is any less arbitrary than the existing figure. If anyone is going to be serious about a change then they should produce some sort of convincing and verifiable evidence to support their proposal.
German law for 100km/h towing was changed from 80% weight ratio to 100% and only a change of that order makes any sense. Anything significantly less is just change for the sake of change, otherwise one might just as well keep everything as it is.

 

[ProfJohnL]

Hello Lutz,
I agree that the suggested change to 90% is not a big one, but at least the wisdom of the 85% is now being questioned by none less than the major manufactures. (but then they do have a vested interest in being able to up the mass of caravans that can be towed by a given vehicle)

I am convinced the matching of outfits by mass ratios against a static nominal figure is highly inaccurate and far too simplistic. The subject needs a properly funded study to firstly quantify the scale of the problem, and then to produce a method of predicting stability and how effective different measures are at helping to minimise the onset of instability.

 

[carper2]

I think that the 85% really applies to people new to towing the thing is it is not law. The more experienced people will make their own decisions as some even now tow at 100%. I would be comfortable towing at 90-95% but I still stick to around the 85% mark through choice.

Les

 

[ProfJohnL]

Hello Carper,

It is off course a matter of personal choice, and I have no issue with individuals that choose to tow with ratio’s around 85%, through practical experience of their outfit and the way it behaves, then I am all for it, but if its used because the driver is ‘following’ the advice from the clubs with no reference to the actual behaviour of their outfit then it could well be wrong and I have an issue with that.

Good sense suggests that a trailer should be as light as possible compared to the tow vehicle, but there are some vehicles around that are more than capable of handling a trailer at over 100%, and there are some others that are incapable at 85% so a fixed figure compared to the vehicles kerb weight is not particularly helpful or necessarily safe solution.

The capability of the car is ignored, yet by law all new cars sold in the UK have to be rated for towing, and manufacturers have to publish max towed weights as part of the vehicles type approval process. This was not the case when the 85% suggestion was agreed on.

It has to be recognised that the manufactures are quoting masses for ideal trailers, and caravans are far from ideal, having large surface areas and relatively high Centre of masses both of which adversely affect towing and stability. So it would make more sense to suggest a percentage of the cars towing ability rather than its kerbweight.

 

[TheTravellingRooster]

Hi to you all out there.The debate as to the continuity of the recommended 85% towing limit for 'Newbies' and relatively new caravanner's is a very subjective one. All of the figures involved in the "Correct Setting Up" of the caravan & tow vehicle are based on optimum conditions;that is to say; Static. No fidgety kids in the back, no cross winds,no big lorries & coaches,no uphill or down hill,no sudden change of camber/road surface and most definitely;no ruts in the surface that can be so deep that they resemble miniature dry canals. To put this into another parameter, lets look at Banking on Line. Everything that is ideal about it (or so we convince ourselves to that effect) goes swimmingly until a computer crash;or worst still a total power failure.Our reliance on technology is becoming dire.Our once thriving manufacturing bases and history is in tatters and a reliance (that word again!) on others for the essential bits to run the Wonderful World of Technology is becoming questionable. The possibilities of no money(ATM shut-downs),no shopping (no cash-back),no fuel etc, etc, etc.. Now back to the point in question,the modern car with all of the gizmo's/toys that they are heavily laden with and a great many rely on; would be a piece of junk if they failed to perform as is expected of them. Have you watched the antics of drivers when the reversing aid (camera) won't work,or the distance sensors on the bumpers fail. Better still,have you seen a car after it has hit the kerb in bad conditions and the front wheel has folded under the body!,the driver pleading that the Traction Control & ABS worked a treat only a few minutes ago. In a year or two there will be armies of drivers asking why the 'thingy' didn't stop me from hitting the car in front when it suddenly slowed down;oh and I didn't see any brake-lights either. Can you begin to imagine the results of a dual failure in adverse conditions;of the ABS & Traction Control on the tow vehicle & the ATC on the new generation caravans,then to cap it all the bewildered driver says "but Towsafe said that my vehicle kerbweight was ****kgs.
I believe that there is a case for a reduction in the 85% recommendation because of all of this new reliance on "Technology Takes Over". This would not only serve the beginner,it could also serve to protect other road users in the event of a real whoopsie. There is even a good case for an "I'm new to towing" identifier label/plate and an advisory maximum speed of some 10-mph below the 60mph & the 50mph. The idea of advising new caravanner's to not using Motorway Routes until a probationary mileage of towing has been accomplished on regular roads would not go amiss.
The key to all of the calculations is The Kerbweight of the Tow-Vehicle. This has been buggered about with to the point of total disbelief. In some cases the information is so laughable that it is contributory to the unnecessary buying of large fuel guzzling 4x4's.
Add to that the current trend of caravans increasing in weight ( customer demand; for home from home items) where is our hobby/interest going to end up?.

 

[Lutz]

I'm a bit baffled by UK caravanners preoccupation with weight ratios. In most countries over on the Continent it's not an issue. They just abide by the max. allowable towload and that's it. There is no recommendation. Only in Germany is there a legal 100% weight ratio limit (along with other conditions that must also be fulfilled) if you want to tow at 100km/h instead of the regular 80km/h speed limit. Despite that I can't say that I've seen more caravanning accidents over here than in the UK. While I don't wish to dismiss the 85% recommendation (or whatever it might end up as) outright as it does provide some sort of starting point, it does seem that it's often taken a bit too seriously. After all, there are so many other factors which also play a part in determining stability, and some are equally, if not more important, that there seems little point in placing too much emphasis on the figure. When I read of people discussing the relative merits or otherwise of towing at say, 83% versus 87%, I wonder what it's all about.
As yet no-one has come up with any data which would suggest that there is a breakpoint ratio above which the risk of instability suddenly increases beyond an acceptable level. Experience indicates that it is more a sliding scale and everyone must decide for themselves what they are comfortable with. It may even be that one outfit may handle completely differently to another at the same ratio and all other conditions being equal, too.