Towing, driving me mad!

[Stephen4]

Hi, I have been caravanning for years, my last outfit was a Bailey Pegasus series 1 534 and a Volvo V70 2.4 auto, towed like a dream. Recently the van was changed for a Bailey Unicorn Valencia, same car, I know the Unicorn is a little heavier but the towing characteristics are awful. Just been in France for a while and the van wanders and couple of times snaked, we know how to load a van, with the weight over the axle so I am bereft as to what can make such a vast difference, any ideas?

 

[Parksy]

This might seem like a silly reply but have you checked the tyre pressures on the car and the caravan? Would the Volvo need different tyre pressures to tow a heavier caravan?

 

[Stephen4]

I keep the tyres at the recommended level for a full load (38PSI)

 

[Sproket]

Have you checked the stabiliser pads for contamination or excessive glazing.

Has the van got AL-KO atc fitted ?

Has the van got shock absorbers fitted ?

How do you check your nose weight ?

 

[Gafferbill]

.........and I would have the nose weight at the maximum for your car which I believe is 90kgs.

 

[Stephen4]

The van is virtually brand new, I hope pad wear will not be an issue. Yes it has ATC, and hock absorbers, I check the nose weight with a gauge.

 

[Stephen4]

t's pretty much what we run it at. I worry however that with the gas removed to the side, (not quite over the axle) that you have the gas, the fridge and the cooker all on one side, opposite there is only the battery and the contents under the bed to compensate.

 

[Dustydog]

Steve

You are clearly a seasoned caravanner and need no help on how to load.

Are the caravan wheels and tyres correctly balanced.
Does the ATC green light illuminate as soon as you connect to the vehicle?
Do you hear the ATC going through it's self assessment cycle on hitching up?
Traditionally Bailey's are nose heavy from the factory so I'm fairly certain you are not running too light especially as you check it.
Can we assume the tow bar and hitch are not loose?
I see your point about the fridge position etc.
Before spending money at a weighbridge why not ask your dealer and Bailey for their technical Input?
Perhaps your dealer can hitch up another Unicorn for you to try?
Let us know how you get on.
It's probably something simple. Hopefully.

 

[Len_Cuff]

My 2pennyworth
We had a 2000 ABI Yorkshire Rose van MTPLM around 1100Kg. Towed without any problems with my Vectra C V6 CDTi as you would expect. Upgraded to an Adria Adora 612DP with MTLM around 1500Kg. Still within the limit of 1600Kg for the car. Both had Alko hitches and I have to say that I've noticed virtually no difference except I have to remember that I have about an extra 4 foot hanging from my rear

I have to admit that I don't check the noseweight with anything but myself! I load as normal - note the new van has a huge rear locker accessible from both sides - by simply lifting the tow hitch lever. Never had any sign of a snake and I have towed in some pretty bad cross winds on the A17 down to Kings Lynn from Lincoln

 

[Royston]

Both your recent and present vans have similar layouts, not much of a load increase with your present van , both vans must have been fitted with AL-KO ATC Trailer Control .
My present van a Senator series six has a AL-KO Trailer Control fitted ,when I first inserted the 13 pin trailer plug into the car socket the trailer control system erupted like a snorting elephant as it went through its testing sequence.
The Caravan fitter who noticed my reaction to the sudden noise, remarked we can disable the AL_KO system if you wish, no way was my reply, Just wonder if your AL-KO Trailer System has been disabled which could result in latest problems.
Royston

 

[ProfJohnL]

Hello Stephen,

As others have suggested the first thing to do is double check all the things you can such as tyre pressures and wheel nuts and you loading regime.

It may be just worth looking at as sometimes familiarity can blind us to a basic fopar

http://www.practicalcaravan.com/advice/mpage/6
Your description makes me wonder if the caravan wheels are not correctly aligned. This is not something you can check easily, but do look carefully at the wear of the caravan tyres, if its uneven that could be the result of misalignment.

Only a specialist Alko dealer can give a detailed alignment check.

Royston,

You should always match the car and caravan such that even without ATC the outfit is essentially stable.

The Alko ATC system is designed to kick in if you inadvertently exceed the normal operational envelope. It rather like seat belts.

Its not designed to correct a bad match.

 

[JonnyG]

assuming the caravan still has warranty or a guarantee as it is recently purchased? i wouldn't go struggling to find out why, given as the list is endless of things that could cause these issues even an oval tyre could be the cause or your cars rear suspension not being what it was ....get the dealer to check it out voice your concerns and good luck

 

[Royston]

Prof john
I heartily agree with your comments, but if you are used to towing with clever devices, you will never know if you have a miss match, hence if the ALKO system is not working , this could be the result.
Royston

 

[JohnMW]

Sorry -this was addressed to Stephen

 

[ProfJohnL]

Hello John.

You are quite late to this topic, and I suspect from the language you have used your are working under a misapprehension. You seem to think Stephen quoted the pressure in his caravan tyres.

This might seem like a silly reply but have you checked the tyre pressures on the car and the caravan? Would the Volvo need different tyre pressures to tow a heavier caravan?

I keep the tyres at the recommended level for a full load (38PSI)

Stephen does not mention the 'Van' and this is not the sort of comment a caravanner would make about his caravan tyres as caravan manufacturers do not tend to suggest changing tyre pressures for different loads. Coupled with the value of only 38 psi this looks more like and sound like the tow vehicle tyre pressures. This make sense in the context of Parksy's previous comment where he questions Volvo's method of dealing with heavy trailers.

Your further comments about the effects under inflation are still valid whether its for the caravan or the tow vehicle, but very few caravanners will have access to or understand all the tyre data you suggest. I venture to suggest the caravan most likely will have tyres conforming to the OEM handbook specification for the caravan.

Whilst such detailed calculations may be entirely appropriate for commercial HGV trailers, the differential load demands on caravan tyres are rather different.

On a HGV trailer the Payload can easily exceed the trailers ULW. So the tyres have to cope with a very wide range of loads. In a caravan the Payload is a usually less than 20% of the caravans MIRO (ULW) so the possible change in tyre load is much smaller.

Its generally impractical for caravanners to adjust tyre pressures according to the caravans running weight, as they don't have a ready means to weigh the caravan on a trip by trip basis. So with such a relatively small payload, sticking with the tyre pressures set for a caravans MTPLM is unlikely to produce detrimental effects when running with small or zero payloads.

 

[MichaelE]

ATc does not correct a miss matched caravan, it kicks in if you have a severe snake or pitch.
Do not think that it continually monitors your van and corrects it,it does not, it is purely there as a safety device a bit like ABS.

Your match should be pretty good, have you checked the vans nose weight with everything loaded?
As mentioned check all your tyres and clean the towball.

 

[JohnMW]

Hello John.

You are quite late to this topic, and I suspect from the language you have used your are working under a misapprehension. You seem to think Stephen quoted the pressure in his caravan tyres.

This might seem like a silly reply but have you checked the tyre pressures on the car and the caravan? Would the Volvo need different tyre pressures to tow a heavier caravan?

I keep the tyres at the recommended level for a full load (38PSI)

Stephen does not mention the 'Van' and this is not the sort of comment a caravanner would make about his caravan tyres as caravan manufacturers do not tend to suggest changing tyre pressures for different loads. Coupled with the value of only 38 psi this looks more like and sound like the tow vehicle tyre pressures. This make sense in the context of Parksy's previous comment where he questions Volvo's method of dealing with heavy trailers.

Your further comments about the effects under inflation are still valid whether its for the caravan or the tow vehicle, but very few caravanners will have access to or understand all the tyre data you suggest. I venture to suggest the caravan most likely will have tyres conforming to the OEM handbook specification for the caravan.

Whilst such detailed calculations may be entirely appropriate for commercial HGV trailers, the differential load demands on caravan tyres are rather different.

On a HGV trailer the Payload can easily exceed the trailers ULW. So the tyres have to cope with a very wide range of loads. In a caravan the Payload is a usually less than 20% of the caravans MIRO (ULW) so the possible change in tyre load is much smaller.

Its generally impractical for caravanners to adjust tyre pressures according to the caravans running weight, as they don't have a ready means to weigh the caravan on a trip by trip basis. So with such a relatively small payload, sticking with the tyre pressures set for a caravans MTPLM is unlikely to produce detrimental effects when running with small or zero payloads.

 

[tj_4]

I had an issue very similar to this a few years back when I transfered from a Vauxhall Carlton to a Ford Granada. In theory the Granada was heavier, more powerful and should have made a much better towcar bit it didn't. Like you I has instability issues, this was the days before the internet and finding out information a little more difficult. I tried all the things you did without any improvement. Nothing made any substantial difference, including changing to air shocks on a brand new car.

Eventually I changed the caravan, sold the Abbey Oxford and bought a Eccles Emerald, same lemgth, same weight, same layout! But towing was a dream, back to a stable unit.

The conclusion I came to was that the airflow over the two cars was different and this effected the caravans differently, as their bodyshell shapes were slightly different.

Ever since this situation which was in 1993 the change of any car or caravan has been done with great care and intrepidation as you never know the towing charicteristics until you pull a loaded unit.

I have never had a combination as bad as the Granada/Oxford since then, but have noted that there are considerable differences between different combinations, they are not always explainable by compairing power, torque and weights. There are other issues which effect like, overhang, vehicle size and height, tyre profile, loading, sideways movement in rear suspension, tow bar height, and wheelbase.

Good luck!

 

[ProfJohnL]

Hello John.

You are quite late to this topic, and I suspect from the language you have used your are working under a misapprehension. You seem to think Stephen quoted the pressure in his caravan tyres.

This might seem like a silly reply but have you checked the tyre pressures on the car and the caravan? Would the Volvo need different tyre pressures to tow a heavier caravan?

I keep the tyres at the recommended level for a full load (38PSI)

Stephen does not mention the 'Van' and this is not the sort of comment a caravanner would make about his caravan tyres as caravan manufacturers do not tend to suggest changing tyre pressures for different loads. Coupled with the value of only 38 psi this looks more like and sound like the tow vehicle tyre pressures. This make sense in the context of Parksy's previous comment where he questions Volvo's method of dealing with heavy trailers.

Your further comments about the effects under inflation are still valid whether its for the caravan or the tow vehicle, but very few caravanners will have access to or understand all the tyre data you suggest. I venture to suggest the caravan most likely will have tyres conforming to the OEM handbook specification for the caravan.

Whilst such detailed calculations may be entirely appropriate for commercial HGV trailers, the differential load demands on caravan tyres are rather different.

On a HGV trailer the Payload can easily exceed the trailers ULW. So the tyres have to cope with a very wide range of loads. In a caravan the Payload is a usually less than 20% of the caravans MIRO (ULW) so the possible change in tyre load is much smaller.

Its generally impractical for caravanners to adjust tyre pressures according to the caravans running weight, as they don't have a ready means to weigh the caravan on a trip by trip basis. So with such a relatively small payload, sticking with the tyre pressures set for a caravans MTPLM is unlikely to produce detrimental effects when running with small or zero payloads.

Hello JonMW

Your last post didn't seem to have anything added by yourself, What was your point?

 

[xtrailman]

Hi, I have been caravanning for years, my last outfit was a Bailey Pegasus series 1 534 and a Volvo V70 2.4 auto, towed like a dream. Recently the van was changed for a Bailey Unicorn Valencia, same car, I know the Unicorn is a little heavier but the towing characteristics are awful. Just been in France for a while and the van wanders and couple of times snaked, we know how to load a van, with the weight over the axle so I am bereft as to what can make such a vast difference, any ideas?

My experience changing from a 1333kg Senator to a 1565kg Valencia V1 was much the same.

Towing with an Xtrail T31 involved much playing with nose weights, eventually found for the Xtrail 90 to 95kg gave the most stable tow, but reducing speed to 55mph also greatly helped.

Since changing cars to a Mazda CX-5 with a shorter overhang and stiffer suspension, and 55 profile tyres, the tow is noticeable more stable.
The CX-5 only has a poor 88kg NW limit for a SUV, but I find 80 to 88kg NW gives the best tow.

With the V1 Valencia is hard work to get down to 80kg but can be done.
I would suggest trying different NW limits, I also believe the more upright front on these caravans leads to aerodynamic inefficiencies.