Towing limits

[colin-yorkshire]

one other point I forgot to mention the old caravans of the era

used crossply tyres as did most of the cars, stabilisers were not fitted as standard and bearly used at all exept for the real enthu'siast's. who towed regulary.

 

[Lutz]

Quite apart from any discussion concerning the determination of any fixed percentage, whether it be 85%, 90%, 80% or anything else, it should not be forgotten that these weight ratios always represent a worst-case scenario that most people will never encounter in practice. It is therefore of academic interest only as a tool to compare outfits, but not to assess their absolute suitability. A weight ratio of 85% calculated on the basis of MTPLM versus kerbweight, as is standard practice, can easily correspond to an actual weight ratio of under 65% once car and caravan are loaded up.

 

[ProfJohnL]

Hello again Gary,

I find I cannot agree with several of your points, and at the risk or repeating issues I have already put forward I will try to explain why:-

I have not suggested 85% should become enshrined in law, that would be quite unworkable, not least because it is only applied to caravans, and is is actually quite difficult to define a caravan as a small subset of trailers to which the general towing regulations apply.

The current regulations are quite adequate, and in essence they rely on the technical data supplied by the tow vehicle manufacturers. This allows for the full scope of the tow car to be used, and not arbitrarily limited. With the exception of post 1997 drivers 100% ration and 3500Kg GTW defined by their licence- not the technical capability of the car.

The nose load limits are not arbitrary but again are derived from evidence based design and testing of the components used by the manufacturer's. Where someone does exceed a legal limit then what is wrong in bringing it to their attention?

I agree that 'experience' can be difficult to attain, but just as with any new task, you start with variables of low risk and build up carefully until you begin to find that the task is becoming less manageable, and then back off to bring things back under full control. The difficulties of towing are many fold, and what is safe under one set of circumstances may not be safe under different circumstances, so caution is always safest protocol.

I agree with you that modern cars are built using CAD modelling, but also real life testing, and that towing capacities are not a major sales point, but to conclude that manufactures will state a tow limit that that will exceed the safety margins of the design seems illogical. If manufactures were deliberately doing this, then there would be quite serious consequences for them. They would lay themselves open to massive claims under the SoGA (faulty design. Not fit for purpose), Trade descriptions and quite probably other EU regulations on the construction and specification of road vehicles. Equally the same would apply to usable power of the vehicles to move the masses they specify.

I do recall that electronic safety aids have been discussed, but I don't remember any advocating they should not be fitted, I seem to recall that the discussion was about some drivers who drive to greater extremes in the hope that the action of these devices will warn/curb/control their excesses.

 

[xtrailman]

May i point out re the comment from colin "this was the era in which the 85% rule was born and bears no relevence for todays tow cars or the vans we choose to tow them with."

Sorry colin not true, The CC recomendation was a lot lower somewhere near 75%, it has been increased to take account of the improvements in car technology. Increasing from 85% has also been discussed and dismissed.

On the otherhand were apart from the recent ATC, has there been any serious improvements in the caravan?

Not all vans are sold with Alko stabilisers, or ATC.

Short of WEIGHING both car and van before every journey, how can you hand on heart, claim to be towing legally?

If you are towing near 100%, you don't.

I have the gadets on my new xtrail, but do they work?

Don't know.

These driving aids remind me of the safty pressure switches we had at work, you only found out if they worked when they should of done , but didn't!

So i'm not about to start towing at 100% on the streghth of that.

I have had one snake, and lived though it, but at the time i thought i was about to die, luckerly i had read about it, so i knew the theory. Let me tell you it is very difficult NOT to brake, when the front of the car is pointing towards the central reservation one second then the next to the hard shoulder, although you are not surposed to correct the steering i did. And would again, i would also apply gentle braking pressure if required, but would my ESP do that for me?

Hope i never get to test it.

And that gentlemen is why i feel i must say something when the 100% brigade start to sound off.

For those interested, when i had my snake, my towcar was a Toyota Carina2 1.6l, towing a swift corvete 4berth.

Speed was under 65mph, the snake started after a single deck coach overtook at speed.

I did not have a stabilizer fitted as an EXPERT had told me i didn't need one!

I have no doubt in my mind that a stabilizer would have dampened out the snake quicker.

I will never tow with out one.

 

[Lutz]

As the weight ratio is based on a condition which does not reflect a real live situation, I don't care what the recommendation is, whether it be 85%, 100% or anything else. Within the manufacturer's limits I tow what I feel comfortable with, with due regard for the driving conditions and my ability to adapt to those conditions.

I find it alarming that people don't know whether the technical safety devices fitted to their car actually work, given the ability to check them (obviously this won't apply to airbags, for example). The first thing that I would do after taking delivery of a car would be to try the ABS and ESP out. I'd feel uneasy not to know whether they actually do the job intended and I want to know how they react when they do deploy, which could be different from model to model. I wouldn't want to get a bad surprise right in the middle of an emergency situation, which could result in a panic reaction on my part.

 

[colin-yorkshire]

hi ray

I dont know where you source the info from but I distictly remember my CC handbook circa 1968(ish) recomending a load limit of around 85% before that the only car safety features over the older models was disc brakes. the first car that I am aware of that had abs was the audi 100 around 1971, crist most cars before 1968 did not even have servo assisted brakes.

in my 43 years on the road 30odd of which towing trailers I have seen 10 overturned caravans nearly all of which has been in the last 4 years 8 of them involved a (sorry guys) 4x4 1 was a transit van the other was a volvo 740 that some how lost the van off the back, the brakaway chain locked one wheel but not the other it turned sidways hit the barrier and rolled over. how do I know I was 50yds behind him when it happend.

none of the vans I have seen on there side can possibly have been over 85% because of the size of the towing vehicle.

one last point as vans get heavier and cars get lighter 85% trailer weight is becomming harder to achieve, unless we make the only tow car available a 3ton shogun, when that happens (if ever) I for one will stop touring.

colin

 

[colin-yorkshire]

oh and nearly forgot on the subject of stabilisers I allways use two the alko and a scott.

ps. don,t anyone start on about this my ears are still ringing from last time I mentioned it.

 

[ProfJohnL]

Hello Ray

I think some of your last posting needs further debate.

"Short of WEIGHING both car and van before every journey, how can you hand on heart, claim to be towing legally?

If you are towing near 100%, you don't."

I agree with the first sentence of the quote, but the second does not make sense. If you are implying that the legal limit is 100% then you are in error. The only time 100% comes into legislation is in reference to the cat 'B' standard driving licence, and that is a limit on the driver not the outfit.

The legal limit is effectively the max towing limit set by the manufacturer. This is not a fixed figure but varies for each make and model of car sold in the EU. - What must also be considered is whether the outfit is safe, and that is not defined by weight ratio alone.

Your own experiences have led you to be cautious, and that is no bad thing, I am obliged to point out that if you were exceeding 60mph in the UK then you were already committing an offence, but I am glad that you came through it only shaken and somewhat wiser, but you are relating the difficulties you had to weight ratio alone, and that is not a logical conclusion. Snaking can be induced on many outfits through driving habits, which is in my view the greatest cause of snaking, but the onset of snaking can often be improved by redistributing the weight in the trailer, and of course by altering driving habits (such as speed, change of direction and braking), and awareness of the conditions around.

The trailer weight has to be within the tow vehicles specification, but it is always a good move to try and keep it as low as possible, so I am not against the principal behind the 85% guideline, but I am against the arbitrary nature of the figure and some of the hype surrounding it which tends to give the erroneous impression that an outfit will be safe if 85% is observed.

The use of add on devises such as stabilisers is a sensible precaution, but it is unwise to rely on a stabiliser to control an outfit if it is inherently unstable without it. These devices should be considered in the same way as safety belts and air bags, as being there to help to when things get out of normal control.

 

[xtrailman]

To further the debate.

Lutz,

Not for a minute did i expect you to agree that towing at 85% was sensible.

My xtrail has a max tow of 2200kg, i'm sure you would feel cofident to tow to this figure, secure in the knowlege, that you are legal to do so?

However i consider the 2200kg max trailer load to be intended for trailers other than caravans.

As for testing the ESP and ABS, well i am still running in the car, so i feel this would not be sensible, nor does Nissan advise heavy braking etc, during the running in period.

How many times when going to a breakdown have i heard the operator say "it was working ok earlier".

And the point is, a test does not guarantee the system will work when required.

But yes i agree it would be a good idea to test the systems, when the car is run in.

Colin

Re the CC 85% the imformation i refered to was in the anwser to a simular question from a club member, in the CC club.

I usually see a caravan overturned every year, very alarming.

All the more reason to tow well within safe limits.

I suspect overconfidence is the reason for so many 4x4 being involved in these incidents.

I agree weight alone is not the only safty factor. But it is at the top of my list.

You say cars are getting lighter, well not any cars i have had, everyone has got bigger and heavier. For example, my old xtrail was around 1650kg, the new one is around 3" longer and 60kg heavier.

I certainly woulnt berate you for having belts and braces on the stabilizer front, but i would be concerned about the stress placed on the tow bar?

John L

At no time have i refered to legal limits.

To tow over or near to 100% is folly, and can only reduce safty margins. I refer to towing a caravan, not trailers.

You point out that i was doing a indicated 65mph, this usually signifies a speed nearer 60mph actual? So i do think you are nit picking.

I tow around 60mph generally, and as with every one else, my speed will flutuate above and below this figure.

Regarding my snake, it had nothing to do with the weight ratio nor did i imply it did. Rather i mentioned it to draw attention to the usefullness of having a stabilizer fitted to bring the rig back into control a little quicker.

As for the snake being induced by driving habits, the rig was on a slight down gradiant, running in a straight line.

I don't know the reason for the snake, but i now always try to move to the left of the lane when a coach/lorry goes bye.

Which nowadays isnt as often as it used to be thanks to speed limiters.

 

[colin-yorkshire]

hi ray

I think I know where you are comming from and do understand your points, so a bit of clarification may be in order, to start with I responded to the thread because I am a member of a few forums and the times newbies and the returning back to caravaning posters request information on towing weights quoting the magic 85% ratio is unbelieveable at least 4 or 5 times a week because they are worried that their unit does not comply without realising it does not have to. My answer is allways the same. The 85% rule is a recomendation only that should be taken with a very large pince of salt, the only thing that matters is that the nose weight must not be exeeded the lighter of the 2 figures (either car or van) and is the one that must be adheard to, the MTPLM of the van must not exeeded in any circumstances yes the nose weight can be deducted from the MTPLM for the purpose of legality but without it there is far less chance of overloading the van. and when all the weights have been added together they must not exeed the towing vehicles gross train weight. if nessesary get the whole outfit weighed on a weighbridge, car, then van, then the complete unit

to me this is the only way to be absolutly sure the unit is legal.

secondly stability the biggest cause of instability is poor loading not excess weight a van loaded badly will be far more unstable at lower speeds than a heavier one correctly loaded at a higher speed all heavy items should be low down on the floor and between the axles or placed in the car to disribute the weight more evenly. The lower the centre of gravity is and the better the balance front to back is, the better the stability of the unit is going to be.

tow car weights yes I agree some cars have got bigger and in doing so got a bit heavier like the laguna, mondeo,ect but I was talking in general terms not about individual models 10 years ago probably the most popular tow cars were volvo's granada's ect but with rising fuel prices tax costs ect owners have to look for cars that are cheaper to run on an every day basis while still being able to tow the van when it has to, so they go for a smaller lighter model that will do the job.

and that ray is exactly why I went for the megane 1.9 diesel it could have been a pug 307 or octavia but something along the same lines but definitly not an Xtrail shogun or disco because the increased cost of running one would reduce the times I get away in the van. incedendly this may also be the reason there seems to be more seasonal piches around and why sites that offer year round storage are full to capacity.

and finaly driving styles this is probably the second most important aspect of towing, some do drive round with a van on the back the same way as they do solo and there is no wonder they get into trouble, hurtling down the m/way at 70 with the van wagging its tail like a demented terrier just hoping the alko ABS and ATC's and what have you work well enough to avoid a catastrophe.

ok so I tow with a smaller car and a lighter van that is a 97% match it does the job perfectly and is 100% stable I also have the confidence (and the weight certfiicate) to know how to load everthing car and van for optimum performance and safety. while not perporting to be the worlds best driver or an expert in anyway after 30odd years of towing all types of trailers I have never had a problem while towing, I do feel my experience and others like me may be of use to the odd novice that comes along and askes a question though.

colin

 

[ProfJohnL]

Hello again Ray,

Your points in order of appearance in your last posting:

As I stated in my last reply, It was not clear what your

"Short of WEIGHING both car and van before every journey, how can you hand on heart, claim to be towing legally?

If you are towing near 100%, you don't." Actually meant.

You do refer to towing legally and in the context of the headline thread that has a legal limit implication. It is only your contention that it is folly to tow at or near 100%, clearly the car manufactures who do actual tests often don't agree with that contention. I accept that caravans have particular issues to do with size and that might have a bearing on what represents a safe outfit.

Your initial response did not state your speed was "indicated" so I had to assume you meant real speed. However the point is largely academic as any car driver with a trailer travelling faster than 60mph (real speed) is committing an offence in the UK. It does not diminish the offence if other drivers are also doing it. I am guilty of nit picking on this, but I am right.

You are prepared to stick to 85% weight ratio guideline, which has no legal significance. And you are prepared to exceed a legal speed limit!

I have to assume that when your snaking incident occurred, you were compliant with the 85% ratio. If this is true, and despite this you encountered a snake. This goes to show that the 85% figure is no guarantee of a safe outfit. There must be other significant factors involved.

I note that your corrective action was to allow the outfit to slow down. This implies you were travelling too fast when the incident occurred. Speed is a driving habit, and thus is the major contributor to instability incidents. You should adjust you speed to compensate for road and other conditions.

 

[xtrailman]

Johnl

Is your post serious?

Or just a wind up?

 

[Lutz]

I can find no reason to criticise John's reply from a technical perspective so I don't see why one should cast doubts on its seriousness.

 

[ProfJohnL]

Ray

You may view my post in any way you wish, but It was not composed as a wind up, it was my comments and conclusions based on some of the content of your postings.

I think there is now enough information on this thread and I am sure the great and good will be able to read and decide which point of view has most merit.

 

[xtrailman]

Still working the double act?

 

[Zafiral]

John's comment about the majority of 'inidents' (let's hope that is all they were), agrees with a point I made a few months ago. 4x4s are inherently less stable than normal cars (owing to the higher C of G for starters) so I fail to see how a early 90's 4x4 (a good few of them don't even have ABS!!) makes a better towcar than a modern family hatch. In these cases, it may be the car which lost control and flipped before the van.....

BTW I am not anti 4x4s and if money was no object my favourite towcar would be an X5.

 

[gary]

I might be able to offer one reason why early 90's 4x4's are better?

That is narrower wheels and or different track, this changes the way the thing behaves on motorways due to not being affected by inside lane tram lines.

This comes from a customer who pulled a car trailer up and down motorways for a living with a 300 series Disco.

He mentioned the Disco was on original skinny steel wheels and did not suffer at all from tram lines making the Disco weave, unlike he said those with those posh wider alloys?!

 

[xtrailman]

Gary

The Audi A4 Avant Quattro i had was a nightmare for tramlining, 225/45 tyres i am sure was the main reason.

The sports suspension was too hard for our roads, road humps and potholes were best avoided.

At the time the Omega was another car that suffered from the same problem.

Oddly the xtrail on 215/65 did not have the same problem.

 

[Lutz]

The comments regarding the tramlining effect of wide tyres are legitimate, but this should not be taken to be a general criticism of the respective vehicle as a towcar. If fitted with different pairs of boots, some of these cars might make very good towcars.

 

[gary]

No I'm not Lutz's, it's a comment based on extensive practical experience of towing with the 300 series Disco, that is opposed to what was the average Caravanners view, that it was a poor tow car.

Another example concerns a dealer, the mk3 Mondeo Estate and similar Omega, both cars were used extensively to tow many different and generally empty caravans.

What he said was strange is how one or other car would tow the same van so differently. One car would tow van 'A' 100% stable and the other far less so. Van 'B' could be just the reverse.

 

[xtrailman]

I agree gary.

The swift corvette i had my snake with, had the aerodynamics of a brick, the front had little slope, and above the bay windows a 3" overhang lip.

When i towed the swift challeger 1992 model, it was much more stable.

 

[Ianofwilts]

I find all these weight issues playing heavy on my mind. I understand the 85% max match van to car I understand nose weights, I understand train weights. My license allows me to drive a vehicle up to 7.5 T and can tow but not exeeding a train weight of 12 T.

I drive an 05 525d BMW. It weighs 1760Kg My van weighs around 1700kg fully laidened. When deciding upon tow car I was more interested in the cars capability i.e. torque and stability. BMW state my car can tow 2000kg breaked. This could be increase apparently but BMW would have to upgrade the self leveling suspension. Car stability comes from dynamic stability control and I must admit with 400lb of torque it tows a dream, is stable and level. I was told by both the caravan supplier after they carried out checks for me prior to purchasing the car and BMW that the match was fine if experienced in towing.

Am I legal ?

And this 85% rule, it was arrived at long before stabilisers and ABS and traction control and other safety features, wasn't it ?

Isn't it about safe sensible driving and experience and not exeeding the vams max mass and the cars towing max ?

 

[AlanChristine]

Having read this thread.I am suprised at the lack of reference to the insurance issues. After doing research before purchasing my present insurance,I found that the "notional" "outdated" 85% rule does apply when insuring a caravan.The more the van exceeds the 85% the less likely they are to pay out in the event of an accident.I found that 3-5% over the 85% from most of the insurers was an "argueable" payout,over this was a definate no go owing to the safety aspects and stabilty of the outfit.So it seems that this "rule" is not just there to keep someone busy,but common sense.It would make sence too to check your insurance before changing your van!

chris

ps:my information came from a Area manager of a well known insurance company.

 

[Lutz]

Unless the insurance policy specifically makes reference to an 85% weight ratio, any attempt by an insurance company to withhold claims on these grounds should be challenged as there is absolutely no justification for such action. No data has ever been produced that the accident risk increases appreciably if 85% is exceeded.

If the area manager made such an unqualified statement, he should confirm that in writing and the matter taken up with the insurance company.

 

[Ianofwilts]

I am insured with the caravan club. The issue of weight was discussed and I was told that the van should not exceed its max ladened weight and not weigh more than that permitted by the car manufacturer. The 85% rule was not mentioned.