A Cautionary Tail when towing on the Motorways.

[stuart_5107319]

Hi Emmerson

If you read my post before exploding, I have never stated that the towcar should not be heavier than the van. What I did say was, there is a lack of understanding about towing and basic physics. After 40 years of towing you will know this better than most. I also did say most paople think that the heavier the towcar - the better. This is what I stated to be boll@ocks. I am sure that with your experience you would agree

Stu

 

[emmerson2]

Stuart, I didn't explode, but I still say that you are not quite correct.As far as most caravanners are concerned, the heavier the towcar, the better the stability of the outfit. If a novice 'vanner tows his 1500kg twin axle with a Renault Clio, he is heading for disaster. Indeed, if an 40year experienced 'vanner does that,then he also is heading for disaster. However, if our novice sets forth with 2250kg's worth of towcar, then disaster just might be avoided. That is the law of physics. QED.

 

[emmerson2]

Probably to be continued, but the Guiness is taking effect. I'm off to bed.

 

[stuart_5107319]

Stuart, I didn't explode, but I still say that you are not quite correct.As far as most caravanners are concerned, the heavier the towcar, the better the stability of the outfit. If a novice 'vanner tows his 1500kg twin axle with a Renault Clio, he is heading for disaster. Indeed, if an 40year experienced 'vanner does that,then he also is heading for disaster. However, if our novice sets forth with 2250kg's worth of towcar, then disaster just might be avoided. That is the law of physics. QED.

Sorry, I misread the explosion - its a liverpool thing. Essentially I agree with you, my argument is about the lack of understanding of towing and physics.

My car is 1650 kg my van is 1200kg. I also have very stiff tyres & supension & ESP+

I just think there is a lot of ignorant people driving units of 3000kg+

 

[stuart_5107319]

Hi Emmerson

Sorry ! Maybe explosion was a bit heavy xx

My van is 1200kg my car is 1650kg

I also have the benefit of ESP+ and sports suspension & RFT tyres.

What I was saying was that there was a lack of understanding of towing and physics - I stand by that

 

[BrianStAlbans]

I just think there is a lot of ignorant people driving units of 3000kg+

Sadly Stuart I think that can also be said about a lot of people towing at way less than 3k ;O)

Brian (".)

 

[stuart_5107319]

I agree

 

[colin-yorkshire]

hi all

interesting thread this I have learned more about towing with 4x4s in 10 mins, than well ever.

I am not suprised though at the instability problems of such outfits perhaps it is somthing to do with the fact that modern vans are more like bungalows on wheels and getting bigger??

and before someone jumps on me with size 15 wellies??? stop and think about it, it's not about the weight of the van but the size, I say this for 2 reasons.

1. as it has been stated before that a lot of big vans have a problem with nose weight being too high when empty, this makes owners load more to the backend to get it down thus increasing the pendilum effect when towing increasing the chance of instability.

2. because of the increased length and surface area of the panels on the side and the larger overhang from the wheels they are more prone to be pushed off course by side winds and vortexes caused by hgv,s so any inherent instability is made worse once the unit starts to weave. add to this high ground clearance, soft suspension, and high side walled tyres would I assume make the recovery of a major sway a lot more difficult to handle.

also let,s not forget speed?? these units towed with big engine 4x4s go like the clappers when towing, many many times has one of these units gone flying past me on the motorway doing 70+.

the other reason I say it's the size and not the weight is because of what garfield wrote:- if weight is so important, can someone answer this, when I bought a new 1550kg speedboat and towed it 100 miles home with my 970kg golf GTI there was no hint of instability at 60 mph and under very heavy braking, when the same boat was towed with the Discovery it started to snake at 60 mph. How is it that a towcar that is more than double the weight is no more or even less stable.

In the olden days (violins out time) when nobody ever thought about weight restrictions insability was not such a problem despite car towing weight being over 100%. I too used to tow a boat, a 17ft cabin cruiser and 50hp outboard on a unbraked trailer behind a mk1 cortina and never got a snake in the 6 years I towed it.(it didn't stop too well I seem to rememer though).

regards colin

 

[tomtom1]

emmerson wrote "I now tow my approx 1500kg van with my 2250kg car, but I still, and hopefully always will, know the van is there.I honestly could not tell you what the noseweight is," If you are using an ALKO Hitch then it the nose weight is 100kg over that 100kg If you load it above that limit set by ALKO than It's only yourself to blame if it breaks !

 

[MikeJE]

Lutz,

Can we have some clarification re. your comment on 1 Jun 02.08 pm. " hold steering wheel steady and brake ". All sources I have come across say hold wheel steady and neither brake nor accelerate.

Mike E

 

[Martin_E]

Lutz,

Can we have some clarification re. your comment on 1 Jun 02.08 pm. " hold steering wheel steady and brake ". All sources I have come across say hold wheel steady and neither brake nor accelerate.

Mike E

That is what I understood Mike E as posted 1 Jun 2007 05:53 PM under Lutz reply.

 

[Martin_E]

That is what I understood Mike E as posted 1 Jun 2007 05:53 PM under Lutz reply.

Sorry stuck it in the wrong slot )o:

 

[emmerson2]

emmerson wrote "I now tow my approx 1500kg van with my 2250kg car, but I still, and hopefully always will, know the van is there.I honestly could not tell you what the noseweight is," If you are using an ALKO Hitch then it the nose weight is 100kg over that 100kg If you load it above that limit set by ALKO than It's only yourself to blame if it breaks !

Alko hitch hadn't been invented when my van was built!

 

[Icemaker]

was there not an issue with run flat tyres not being suitable for towing ?, i seem to remember reading an article in the club mag not too long ago about the tyre manufacturers refusing to honour the warranty on these tyres if they had been used on a tow car.

Was the issue resolved or does it still stand that one should not tow with a car fitted with these tyres?.

 

[Lutz]

First of all in reply to Emmerson's last contribution to this thread:

I'm not questioning for one minute that a high noseweight and a favourable weight ratio help towards improving stability. However, they are not the only factors and there are other ways of avoiding loss of control of the outfit. After all, with the weight of caravans continually on the increase, owners have a legitimate right to expect to be able to tow safely even if irregular trips with the caravan don't justify purchase of a heavier towcar not used to its full capability the rest of the time. It is primarily for these people that engineers are coming up with novel solutions, e.g. electronic stabilisers. There is no reason to suppose that these electronics are any less reliable than vehicle braking systems which are also becoming increasingly computer-controlled.

Secondly, to Martin "E"'s reply:

The caravan will only recover from a snake if its brakes are applied. Maybe you can be lucky enough to make that happen by just removing your foot from the accelerator but the only sure way is to apply moderate braking yourself. This is the same principle as the one on which electronic stabilisers work, whether they are fitted to the car (TSP) or to the caravan (like the AlKo ATC or LEAS systems)

Thridly, in response to Icemaker's post:

I think you may be confusing run-flat tyres with space saver tyres. Space saver tyres may not have the necessary load carrying capacity or handling performance when towing and maybe that is why warranties were not being honoured.

 

[RiaandJames_374303418]

We've briefly owned two Disco's and I've had them as my "works" cars.

Our works units have used Disco's for towing Exhibition style trailers and a we've towed a variety of other trailers with them and they are not my favourite tug due to instability when towing. The new Style Disco may be fine, but the older Disco's leave quite a few towing problems un-answered.

At a steady 50mph with a well loaded caravan they can be fine. Approach 60mph and find a rutted sections of open motorway and and Disco's can react like some on a Disco dance floor even with the best loaded stable caravan in tow.

Having towed the same large matching yacht trailers behind a VW Sharran and then with a new TD5 on the open road the VW was a far superior tow tug whilst the disco was very fidgety and did not inspire confidence in anyone that towed with it.

James

 

[Icemaker]

copy of posting on tyre safes website, i think since this was published the clubs recomended not towing at all with these tyres if they had deflated, meaning they offer no aditional use to the towing vehicle.

the number of new vehicles fitted with this type of tyre is set to grow. Self supporting run flat tyres have specially reinforced sidewalls designed to provide a run on period following deflation.

Different issues come in to play, however, when run flat tyres are fitted to a vehicle that is towing a caravan or trailer says the Tyre Industry Council. In their inflated, normal condition run flat tyres may be used in the same way as a standard pneumatic tyre. Whilst a deflated run flat tyre is designed to cope with the demands of a solo vehicle, the additional mass of a caravan/trailer subjects the tyre to higher stress levels and impacts on the tyre's in-built torsional and lateral stability. The consequence of this is that even travelling at a restricted speed of 80 kph (50 mph), the additional flexibility of the deflated run flat tyres may negatively affect the stability of the car/caravan combination.

To avoid this potential hazard, it is recommended that the distance travelled and maximum speed on the deflated run flat tyre should be reduced. As the vehicle itself has an influence on the tyre's performance, drivers should refer to the vehicle manufacturer's handbook for further information.

As regards run flat tyres and pressure monitoring systems, the same advice applies to a car towing a caravan or a trailer. Run flat tyres must only be fitted to a car that has been designed to accept this technically advanced tyre and has a pressure monitoring system that provides the driver with an audible or visual warning of a deflating tyre. As yet no caravan or trailer is equipped with a pressure monitoring system and hence should not be fitted with run flat tyres

 

[emmerson2]

Lutz, that's all OK in theory, but what happens when the electronics has a glitch? I know they are getting more and more reliable, but they still can, and always will, go wrong.

I have a cousin who works in the aerospace industry.He is absolutely convinced that ,in our lifetime, aeroplanes will be pilotless, flown only by an infallible computer.Note, he said infallible. However, the plane will be fitted with a second computer, just in case!!!No man-made device is infallible, so I stick to my guns - there ain't no substitute for a big towcar.

 

[Lutz]

OK, Icemaker, I wasn't aware that you were referring to driving on run-flat tyres in the deflated condition. In that case your statements are perfectly valid.

If you are questioning the reliability of electronics, Emmerson, we might as well go back to the old days of carburettors instead of fuel injection and braking systems without ABS. However, today's market demands dictate the use of electronics. Without them it would be impossible to meet current emissions and safety standards. Sooner or later this will apply to other chassis systems, too. Vehicles are already being developed without any mechanical connection between the brake pedal and the actual braking system.

 

[RogerL]

Lutz, that's all OK in theory, but what happens when the electronics has a glitch? I know they are getting more and more reliable, but they still can, and always will, go wrong.

I have a cousin who works in the aerospace industry.He is absolutely convinced that ,in our lifetime, aeroplanes will be pilotless, flown only by an infallible computer.Note, he said infallible. However, the plane will be fitted with a second computer, just in case!!!No man-made device is infallible, so I stick to my guns - there ain't no substitute for a big towcar.

Aircraft already use triple systems to reduce the chance of failure but can never eliminate it.

Pilotless aircraft have been around for decades. When the RAF moved on from their '50s Canberra bomber to second-generation jets they stored the Canberras and converted a number of them to pilotless target tugs which are still in use today.

 

[emmerson2]

Aircraft already use triple systems to reduce the chance of failure but can never eliminate it.

Pilotless aircraft have been around for decades. When the RAF moved on from their '50s Canberra bomber to second-generation jets they stored the Canberras and converted a number of them to pilotless target tugs which are still in use today.

yes, but this guy is talking about Jumbos full of passengers!

 

[Martin_E]

Lutz

2 Jun 2007 01:01 PM First of all in reply to Emmerson's last contribution to this thread:

I'm not questioning for one minute that a high noseweight and a favourable weight ratio help towards improving stability. However, they are not the only factors and there are other ways of avoiding loss of control of the outfit. After all, with the weight of caravans continually on the increase, owners have a legitimate right to expect to be able to tow safely even if irregular trips with the caravan don't justify purchase of a heavier towcar not used to its full capability the rest of the time. It is primarily for these people that engineers are coming up with novel solutions, e.g. electronic stabilisers. There is no reason to suppose that these electronics are any less reliable than vehicle braking systems which are also becoming increasingly computer-controlled.

Secondly, to Martin "E"'s reply:

The caravan will only recover from a snake if its brakes are applied. Maybe you can be lucky enough to make that happen by just removing your foot from the accelerator but the only sure way is to apply moderate braking yourself. This is the same principle as the one on which electronic stabilisers work, whether they are fitted to the car (TSP) or to the caravan (like the AlKo ATC or LEAS systems)

Thridly, in response to Icemaker's post:

I think you may be confusing run-flat tyres with space saver tyres. Space saver tyres may not have the necessary load carrying capacity or handling performance when towing and maybe that is why warranties were not being honoured.

----------------------------------------------------------------

Hi Lutz.

If you are going down hill at the time then yes change down a gear and brake lightly but if not then take your foot off the gas and hold her straight.

Have a look under S in this link http://www.practicalcaravan.com/a-z/page2.html

Martin "E"

 

[emmerson2]

Lutz, I hear what you say, but that doesn't mean I have to like it! My point was, what happens when the electonics go wrong? And at what point would the driver know when it went wrong.?It's a bit like ABS brakes: you don't know they're not working till you hit the wall!A neighbour has a new RR sport.He couldn't use it last weekend cos it wouldn't start.The cause was a 30p relay that said one of the doors wasn't shut, or some equally stupid thing.

 

[Lutz]

There is some rather doubtful advice on the pages that pages that you are referring to, Martin.

Firstly, the snake can develop so quickly that you won't have time to change down as soon as you begin to notice instability occurring. I repeat, if taking your foot off the accelerator is enough to operate the overrun brake, all well and good but moderate braking can only improve the effect and can't do any harm. And I certainly don't go along with the recommendation to "loosen your grip on the steering wheel and allow the steering to right itself". Don't under any circumstances actively try to steer out of a snake but I wouldn't leave the car's steering to its own devices. My experience is that it's better to hold on tight without allowing the steering wheel to turn at all.

 

[Martin_E]

Hi Lutz,

Taken from http://www.explorer-group.co.uk/faq.asp

Q: HOW CAN I AVOID EXCESSIVE CARAVAN SNAKING WHEN I TOW AND WHAT SHOULD I DO IF IT STARTS?

A: The Explorer Group has extensively tested our chassis and we are confident of its stability. However, many other factors can influence your towing unit. When loading your caravan put heavy items low down and mainly over the axle(s). You should not stow tins, bottles or heavy items in overhead lockers, during towing. Everything else should be distributed evenly around your caravan, front and back, and each side of the centreline. Make sure to end up with a suitable nose weight.

Should snaking start, if at all possible don't brake and don't compensate by steering into the swings. Just ease up on the accelerator and allow your speed to gradually decrease until the snaking subsides.

Yes I agree with you not to let the your hands relax.