You have confirmed my statements regarding the advantages but did not comment on the disadvantages that I listed. I would be interested in what you have to say to them.
From what I consider pretty vast towing experience with a caravans and trailers I can only comment from experience.
Having built our own works trailers and opted for twin axle set-up compared to prior single axles. The twins run better in a straight line and offer far better stability in all ways.
Having also towed the same race car and eqipment on a twin axle
compared to a slightly lighter twin again the improvement was very noticeable with the twin.
I dont actually notice that twin caravans are that much heavier than many singles. If you have your vans servicd the bakes should not be a problem and I would tather have four sets of shoes stopping 1600 or so kilos than two sets and have found brake wear to be better on twin on both caravans and trailers.
The only need I see for a motor mover is that re the owners age and mobility. We have never needed one where ever weve been with any van.
Having done very high mileage for many years, I guess like many you take note of caravans. We've also traveled with family using the same cars but a twin axle and a single axle. Carrying similar kit and well loaded.
The difference being so differnet that we swapped cars to see if it was the single that made the difference and we swapped vans when leaving La Trinite for the drive to Les Sables.
When we had a caravan written off the garage that cleared the wreck and the French police commented that from experience the accident would have been far worse it it had involved a single axle caravan.
Also when dealing with the insurance assesors they gave the same un invited comment as well.
To me lower centre of gravity also outweigh any slight differneces re weight. 50 kilos more carried higher than in twin axles could exert a whole lot of unwanted forces in and accident sittuation.
Having built our own works trailers and opted for twin axle set-up compared to prior single axles. The twins run better in a straight line and offer far better stability in all ways.
Having also towed the same race car and eqipment on a twin axle
compared to a slightly lighter twin again the improvement was very noticeable with the twin.
I dont actually notice that twin caravans are that much heavier than many singles. If you have your vans servicd the bakes should not be a problem and I would tather have four sets of shoes stopping 1600 or so kilos than two sets and have found brake wear to be better on twin on both caravans and trailers.
The only need I see for a motor mover is that re the owners age and mobility. We have never needed one where ever weve been with any van.
Having done very high mileage for many years, I guess like many you take note of caravans. We've also traveled with family using the same cars but a twin axle and a single axle. Carrying similar kit and well loaded.
The difference being so differnet that we swapped cars to see if it was the single that made the difference and we swapped vans when leaving La Trinite for the drive to Les Sables.
When we had a caravan written off the garage that cleared the wreck and the French police commented that from experience the accident would have been far worse it it had involved a single axle caravan.
Also when dealing with the insurance assesors they gave the same un invited comment as well.
To me lower centre of gravity also outweigh any slight differneces re weight. 50 kilos more carried higher than in twin axles could exert a whole lot of unwanted forces in and accident sittuation.
How a twin axle can not be heavier than an equivalent single axle is beyond me. Surely the second axle is not weightless. Also, the centre of gravity of a twin axle is normally only negligibly lower than that of a single axle due to the ability to use say, 14" wheels instead of 15" ones (or 13" instead of 14"). Add to that a further disadvantage of a twin axle which I forgot to mention is that they are more difficult to level from side to side. I'm sorry but my impression is that in the majority of cases the twin axle is a pure status symbol which is defended with slim objective argument.
If we were to have bought a caravan as a status symbol in the past I think I would have had more of a status symbol buying a new or newer as we have always had used vans before.
We moved to a twin axle for safer towing havin experienced a blow out that appeared to be caused by road debris.
From trailer chassis and the look of some single axle caravan chassis it appears to gain rigidity on the parallel chassis side memebers they appear to be larger than those spread across two axles.
I suggest Lutz that it makes more sense that large European single axles caravans are just a status symbol achieved by safety cost cutting re buying a cheaper single axle to get a big caravan compared to and at the expense of the safety of a twin axle.
I can say with some authority that should a twin axle be badly loaded side to side it will be a more stable tow than a single.
Twins also ride on lower tyre pressures and give a more gentle ride with less stress being ransfered to the chassis and structure of the caravan.
Our last van towed at 32psi or 2.2 bar against single axle van running on 54psi or 3.75 bar or more.
We moved to a twin axle for safer towing havin experienced a blow out that appeared to be caused by road debris.
From trailer chassis and the look of some single axle caravan chassis it appears to gain rigidity on the parallel chassis side memebers they appear to be larger than those spread across two axles.
I suggest Lutz that it makes more sense that large European single axles caravans are just a status symbol achieved by safety cost cutting re buying a cheaper single axle to get a big caravan compared to and at the expense of the safety of a twin axle.
I can say with some authority that should a twin axle be badly loaded side to side it will be a more stable tow than a single.
Twins also ride on lower tyre pressures and give a more gentle ride with less stress being ransfered to the chassis and structure of the caravan.
Our last van towed at 32psi or 2.2 bar against single axle van running on 54psi or 3.75 bar or more.
ps.
The cut up grass argument is drivel really. With good driving it is not a problem and any good caravanner will make good any scuffs in the grass.
Of course with the twin axle the weight will be better spread on soft ground and leave less of an imprint for the next resident on the pitch. Also as it does not sink in so much you will do less damage towing the van away
I'd believe you if someone can produce actual data of the relative accident rates of twin axles compared to single axles. (I emphasise relative, not absolute, figures for each type because there are obviously more single axle caravans on the roads).
Simple common sense and practical physics make a twin axle a safer bet Lutz.
I don't care what you think Lutz, it is safer. My last full year of work I did over 80000 road miles myself and much the same for the past 12 years. I've observed caravans all over Europe apart from towing our own and others caravans and many trailers for thousands of miles each year.
If you actually believe that a single axle caravan can be any where near as safe as twin axle I think you are kidding yourself.
There are to many factors that give the twin the edge if things start to go wrong.
I would also add that I've had two tyres punctured on one side of a twin axle caravan and compared to slower speed accident on a single it won the debate hands down what ever you may think.
I don't care what you think Lutz, it is safer. My last full year of work I did over 80000 road miles myself and much the same for the past 12 years. I've observed caravans all over Europe apart from towing our own and others caravans and many trailers for thousands of miles each year.
If you actually believe that a single axle caravan can be any where near as safe as twin axle I think you are kidding yourself.
There are to many factors that give the twin the edge if things start to go wrong.
I would also add that I've had two tyres punctured on one side of a twin axle caravan and compared to slower speed accident on a single it won the debate hands down what ever you may think.
Provide the facts, Cris, and you will have convinced me. Pure gut feeling that a twin axle is safer doesn't. It's like the argument I've had elsewhere in this forum concerning disbelief that, under certain circumstances, a car towing a caravan can actually have a shorter braking distance than when solo. Test reports prove the case.
I've had 5 single axles and 3 twins and have to say I much prefer the twins axles. Personal preference I know so doesn't prove a thing but I do find the effects of passing lorrys and side winds etc is less, infact almost non existant, with a twin axle.
Brian (",)
Brian (",)
Provide the facts that a single can be any where as near safe as a twin then Lutz.
Just put brain in gear and use simple logic, just because Germany build some good quality vans does not mean they haven't got the twin axle thing wrong.
Having had car, bike, truck accidents and race accidents and problems when towing caravans and trailers I feel I have more than a fair shot re risk assesment.
I love to save money and would not have built twin axle works trailers on a whim.
When all goes well when towing, a single axle is probably OK, when things start to go wrong the two extra wheels and extra brakes add in factors that can only add extra safety.
Just put brain in gear and use simple logic, just because Germany build some good quality vans does not mean they haven't got the twin axle thing wrong.
Having had car, bike, truck accidents and race accidents and problems when towing caravans and trailers I feel I have more than a fair shot re risk assesment.
I love to save money and would not have built twin axle works trailers on a whim.
When all goes well when towing, a single axle is probably OK, when things start to go wrong the two extra wheels and extra brakes add in factors that can only add extra safety.
ps.
One point Lutz, when a caravan starts to pitch. The single axle has nothing to prevent it pivoting on the single axle where the twin has no matter how little that might be.
One point Lutz, when a caravan starts to pitch. The single axle has nothing to prevent it pivoting on the single axle where the twin has no matter how little that might be.
On more than one occasion travelling south between Bristol and Exeter on the M5 on a windy bank holiday weekend we've actually been able to spot the twin axle vans before we got close enough to see they were T/A. They were the stable ones!
If more axles were that much safer then why aren't cars which are capable of speeds well in excess of that of caravans six or even eight wheeled? No manufacturer in the car and truck industry puts more axles on a vehicle than is necessary to take the weight (give or take a few exceptions of special vehicles, such as some motor homes, where loading height dictates the use of smaller wheels which are otherwise incapable of taking the load).
I don't know whether you remember the old six-wheeler Bedford VAL buses of the late 60's? They only had six wheels because Bedford at the time didn't have a suitable axle to take the weight and they wanted to avoid having to retool a new one. The design was sold for reasons of safety but that was pure bluff because no-one wanted to admit that they didn't have the money for a new axle.
When you were travelling down the M5 comparing the way single axled caravans were performing with twin axles were you not also comparing short single axles with long twin axles? A short single axle will always show some signs of nervousness. The longer the caravan, the steadier it tows. That's why the Continentals tend to have longer drawbars than UK caravans. Although they may be steadier, that still doesn't say they are any less safe. Hence, twin axle is personal preference only unless accident data can prove otherwise.
I don't know whether you remember the old six-wheeler Bedford VAL buses of the late 60's? They only had six wheels because Bedford at the time didn't have a suitable axle to take the weight and they wanted to avoid having to retool a new one. The design was sold for reasons of safety but that was pure bluff because no-one wanted to admit that they didn't have the money for a new axle.
When you were travelling down the M5 comparing the way single axled caravans were performing with twin axles were you not also comparing short single axles with long twin axles? A short single axle will always show some signs of nervousness. The longer the caravan, the steadier it tows. That's why the Continentals tend to have longer drawbars than UK caravans. Although they may be steadier, that still doesn't say they are any less safe. Hence, twin axle is personal preference only unless accident data can prove otherwise.
Sorry, I meant to say that although single axles may appear less steady on the road, they are not less safe.
a car towing a caravan can actually have a shorter braking distance than when solo. Test reports prove the case.
what test reports Lutz? how and when did they prove it?
I'm really interested in a caravan that can stop it's own mass with two drum brakes without abs, but not only that can also assist the towing vehicles braking performance to bring it to a halt quicker, let's have the hard facts and the proof please, like when and where the test was conducted, by whom, and towing what combination, and last but not least the braking distances from what speed, solo & towing.
Allan.
what test reports Lutz? how and when did they prove it?
I'm really interested in a caravan that can stop it's own mass with two drum brakes without abs, but not only that can also assist the towing vehicles braking performance to bring it to a halt quicker, let's have the hard facts and the proof please, like when and where the test was conducted, by whom, and towing what combination, and last but not least the braking distances from what speed, solo & towing.
Allan.
I'm sorry, I'm not at home at the moment so I don't have the report at hand but Brian (St Albans) in one of his replies has confirmed that he, too, has seen the same report.
By the way, BPW, the second largest manufacturer of caravan chassis after AlKo, last year unveiled a prototype goosenecked chassis for caravans that would allow 17" and 18" wheels while at the same time even reducing step height (and consequently also the centre of gravity). This configuration would allow single axled caravans of 2000kg or more.
By the way, BPW, the second largest manufacturer of caravan chassis after AlKo, last year unveiled a prototype goosenecked chassis for caravans that would allow 17" and 18" wheels while at the same time even reducing step height (and consequently also the centre of gravity). This configuration would allow single axled caravans of 2000kg or more.
My experience in answer to Lutz comments.
Advantages
1. Moderate pitch control (see above)
....Much less pitching and when the TA does it stops much quicker
2. Better straight line running ability (only applies to short caravans, though. Long single axles are just as good)
.... Agree, the van straight lines in places where my old single struggled. It also self corrects when passed by big vehicles at speed
Disadvantages
1. Extra weight of around 50kg, reducing the available payload
...... Not sure about this one. but I did have the max load increased on our latest van to take into account the Air conditioning and mover
2. Difficult to manoeuvre (generally require a motor mover weighing another 30kg or so, thus reducing the payload even further)
..... See 2. But I would not man handle a TA at all
3. Brakes are more difficult to balance properly (applies when caravan is being serviced)
...... No idea, thats what the dealer is for.
I do have to say that the last 2 vans I have had are an ACE TA and an Bailey TA and of the 2 the Bailey is far more stable. I think its down to the square front of the Bailey that gets more of a push backwoods by the wind thus always keeping a small pull on the car
Advantages
1. Moderate pitch control (see above)
....Much less pitching and when the TA does it stops much quicker
2. Better straight line running ability (only applies to short caravans, though. Long single axles are just as good)
.... Agree, the van straight lines in places where my old single struggled. It also self corrects when passed by big vehicles at speed
Disadvantages
1. Extra weight of around 50kg, reducing the available payload
...... Not sure about this one. but I did have the max load increased on our latest van to take into account the Air conditioning and mover
2. Difficult to manoeuvre (generally require a motor mover weighing another 30kg or so, thus reducing the payload even further)
..... See 2. But I would not man handle a TA at all
3. Brakes are more difficult to balance properly (applies when caravan is being serviced)
...... No idea, thats what the dealer is for.
I do have to say that the last 2 vans I have had are an ACE TA and an Bailey TA and of the 2 the Bailey is far more stable. I think its down to the square front of the Bailey that gets more of a push backwoods by the wind thus always keeping a small pull on the car
As you state, the Bailey twin axle is far more stable than the Ace twin axle. This confirms that there is a lot more to a stable outfit than whether it has one or two axles.
What Lutz seems to be saying is that manufacturers of trailers and horse boxes and the like are either wasting their time using more than one axle or following some kind of one upmanship status symbol fashion trend.
No doubt all the Iffor Williams tuggers (me included) with there twin and tri axle set-ups will agree that those extra axles are just a weight penalty addition that make them look real cool as well a waste of money!
Tyrrell P34 F1 car banned as it was judged to give and unfair advantage, as opposed to Auto Union style twin rear axles race cars that added little or nothing in a race environment. The smaller wheeled friont wheeled Tyrrell have a reduce Aero profile and reduced centre of gravity and increased braking and front tyre footprint and was banned by the FIA as it gave to big an adbantage over tha othe cars in the F1 pack.
Take HGV lorry trailer, their was a trend for HGV trailers that carried bulk as opposed to weight to run on a single axle.
Amongst the problems were found were, structural problems re the chassis weight resting on a single axle and drivers reporting that side wind loads had more off an effect tracking wise compared to twin axled. Also forces on the swan neck and 5th wheel are said to be worse than multi axles that often carry far more weight. Tyre wear is also better on multi's despite scrubbing out on some turns.
Then take the likes of large Van Hool and Neoplan coaches. Twn rear axles took over from singles for a variety of reasons from handling and structural needs, lowereing centre of gravity and on road handling. My understanding is that twin axle coaches spreading the weight over twin rear axles add positives to stability tests re the coaches tipping over.
Back to a twin axle caravans, even with goog braking and stabilisers a trailer or caravan will try and unload its weight side ways under extreme braking and any lower weight or centre of gravity will be more beneficial than high C of G. Extra grip from tyres also adds a positive equation as does lower tyre pressure plus the fact that the wheels try to run straight more son than those of a single axle.
Also with a caravan if some how you get into some extreme cornering a single axle will break away to the side due to less tyre friction easier than a twin of like size.
Re motor movers and twin axles, I've actually seen only a few twins with motor movers. I've never needed one when parking on a pitch and as we could drive our caravans in and turn around in our driveway and garden where we used to live and where we live now I can't see the need for one apart from if you have mobility needs yourself or you have a vary tight space to store the van.
No doubt all the Iffor Williams tuggers (me included) with there twin and tri axle set-ups will agree that those extra axles are just a weight penalty addition that make them look real cool as well a waste of money!
Tyrrell P34 F1 car banned as it was judged to give and unfair advantage, as opposed to Auto Union style twin rear axles race cars that added little or nothing in a race environment. The smaller wheeled friont wheeled Tyrrell have a reduce Aero profile and reduced centre of gravity and increased braking and front tyre footprint and was banned by the FIA as it gave to big an adbantage over tha othe cars in the F1 pack.
Take HGV lorry trailer, their was a trend for HGV trailers that carried bulk as opposed to weight to run on a single axle.
Amongst the problems were found were, structural problems re the chassis weight resting on a single axle and drivers reporting that side wind loads had more off an effect tracking wise compared to twin axled. Also forces on the swan neck and 5th wheel are said to be worse than multi axles that often carry far more weight. Tyre wear is also better on multi's despite scrubbing out on some turns.
Then take the likes of large Van Hool and Neoplan coaches. Twn rear axles took over from singles for a variety of reasons from handling and structural needs, lowereing centre of gravity and on road handling. My understanding is that twin axle coaches spreading the weight over twin rear axles add positives to stability tests re the coaches tipping over.
Back to a twin axle caravans, even with goog braking and stabilisers a trailer or caravan will try and unload its weight side ways under extreme braking and any lower weight or centre of gravity will be more beneficial than high C of G. Extra grip from tyres also adds a positive equation as does lower tyre pressure plus the fact that the wheels try to run straight more son than those of a single axle.
Also with a caravan if some how you get into some extreme cornering a single axle will break away to the side due to less tyre friction easier than a twin of like size.
Re motor movers and twin axles, I've actually seen only a few twins with motor movers. I've never needed one when parking on a pitch and as we could drive our caravans in and turn around in our driveway and garden where we used to live and where we live now I can't see the need for one apart from if you have mobility needs yourself or you have a vary tight space to store the van.
It's the maximum legally permissible axle load of 10.5 tonnes per axle (in the UK) that governs the number of axles HGV trailers have. A 40-odd tonner is therefore going to need a miinimum of four axles (probably five due if the load on each axle isn't evenly distibuted). It has absolutely nothing to do with stability.
Cris
"Having had car, bike, truck accidents and race accidents and problems when towing caravans and trailers I feel I have more than a fair shot re risk assesment.
I would have thought that good risk assessment would have worked to prevent accidents !!!
Val & Frank
"Having had car, bike, truck accidents and race accidents and problems when towing caravans and trailers I feel I have more than a fair shot re risk assesment.
I would have thought that good risk assessment would have worked to prevent accidents !!!
Val & Frank
Cris,
Re motor movers and twin axles, I've actually seen only a few twins with motor movers. I've never needed one when parking on a pitch and as we could drive our caravans in and turn around in our driveway and garden where we used to live and where we live now I can't see the need for one apart from if you have mobility needs yourself or you have a vary tight space to store the van.
I have a TA and use the movers a lot, I find it better to use the mover than tear up the grass when trying to reverse into most CC pitches.
Val & Frank
Re motor movers and twin axles, I've actually seen only a few twins with motor movers. I've never needed one when parking on a pitch and as we could drive our caravans in and turn around in our driveway and garden where we used to live and where we live now I can't see the need for one apart from if you have mobility needs yourself or you have a vary tight space to store the van.
I have a TA and use the movers a lot, I find it better to use the mover than tear up the grass when trying to reverse into most CC pitches.
Val & Frank
Quote - Lutz
As you state, the Bailey twin axle is far more stable than the Ace twin axle. This confirms that there is a lot more to a stable outfit than whether it has one or two axles.
End Quote
Lutz, Could not agree more as i have always loaded these the same way and have towed with the same car. Both have had the same gear in them and in the front box. All in all, I think there is a lot more to stability than just size, weight and COG. The tow car, the unsprung weight and the shape of the van all have a lot to do with it.
I will also note that both of our last 2 vans had increased stability if I put a large roof box on the car. No idea why!
As you state, the Bailey twin axle is far more stable than the Ace twin axle. This confirms that there is a lot more to a stable outfit than whether it has one or two axles.
End Quote
Lutz, Could not agree more as i have always loaded these the same way and have towed with the same car. Both have had the same gear in them and in the front box. All in all, I think there is a lot more to stability than just size, weight and COG. The tow car, the unsprung weight and the shape of the van all have a lot to do with it.
I will also note that both of our last 2 vans had increased stability if I put a large roof box on the car. No idea why!
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