Why do some vans have twin axles and others single?

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Some vans have twin axles while others have single axles because twin axles provide better stability and can handle more weight. This is especially useful for longer or heavier vans, as twin axles help distribute the weight more evenly and improve the van's balance and safety on the road. Even if two vans are the same length, the one with more weight or a heavier load might need the extra support of twin axles.
 
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Some vans have twin axles while others have single axles because twin axles provide better stability and can handle more weight. This is especially useful for longer or heavier vans, as twin axles help distribute the weight more evenly and improve the van's balance and safety on the road. Even if two vans are the same length, the one with more weight or a heavier load might need the extra support of twin axles.

It all depends on what one calls a heavy caravan. Single axle chassis for caravans are available up to 2000kg and very few Continental manufacturers choose twin axles below that. A twin axle doesn't only have advantages over a single axle, but it has disadvantages, too. A single axle chassis is cheaper to produce than a twin of the same weight, and maintenance is cheaper because there is only one set of brakes and two tyres instead of four to replace. Also, the weight of the second axle increases the unladen weight, leaving a smaller payload margin and then there's easier manoeuvrability of a single axle. A twin almost inevitably needs a motor mover.
 
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Motor Movers are 30-35kg a pair which come off user payload along with 28kg for 100Ahr battery. NB battery isn't typically included in MIRO.
If TA needs maneuvering into tight spot then 2 pairs of MMs are needed ie 60-70kg user payload hit. Can get away with 1 pair of MM if only doing gentle turns and even then may need a nudge by operator.

The alternative MM is motorised mover see

Robot Trolley RT1500 Caravan Mover​

Really only good on flat ideally sealed surface. No hit on your payload as it stays at home.

MMs aren't essential when travelling but nice to have.
 
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When putting a caravan onto some pitches in the UK they are essential, and batteries now part of the MIRO.
Battery isn't in MIRO unless stated in manufacturer. Swift basecamp has battery in options section. Bailey Discovery doesn't mention it at all. Caravan don't need battery to operated of 240VAC which is why power lead is in MIRO and battery isn't.

 
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JRT

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Having had both I would like to have a Twin when towing and a single when on site and storage.

Anyone else remember the Lunar Delta that had one axle that could be raised using a hydraulic pump?

Best of both worlds, unfortunately it was a great concept not particularly well executed and I don't think it was particularly reliable.
 
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Some vans have twin axles while others have single axles because twin axles provide better stability and can handle more weight. This is especially useful for longer or heavier vans, as twin axles help distribute the weight more evenly and improve the van's balance and safety on the road. Even if two vans are the same length, the one with more weight or a heavier load might need the extra support of twin axles.
There are plenty of single axle chassis that are capable of carrying the largest caravans that c can be towed by domestic vehicles. There is no clear mechanical advantage of TA's. including the the concept that TA 's are more stable has never been proven.

Fundamentally its marketing decision by the manufacturer.
 
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Having had both I would like to have a Twin when towing and a single when on site and storage.

Anyone else remember the Lunar Delta that had one axle that could be raised using a hydraulic pump?
I do remember them, Lunar also did a twin axle 2 berth and (I think) Buccaneer did a twin axle with quite a short (15-feet-ish) body back in the 80's.

Having had a twin axle from 2018 to 2022 I agree they have very good road holding manners and I'd have another without hesitation if we needed to go back tot he longer body. Contrary to what some think, they aren't all heavyweights, ours was a Sprite Quattro with an MTPLM of 1624kgs and towed it with no issues behind a Volvo estate.
 
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In addition documentation pack and hose/ pump for Aquaroll too are included, but not battery unless for self levelling.
I don't think that is correct regarding aquaroll as aquaroll is not a necessity. Allowance for gas bottle is normally up to 20kg. Wastemaster is inclusive if the caravan has an onboard tank, but not the piping. I don't think steps are part of the MIRO either?
 
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The manufacturer is pretty much at liberty what to include and what not to include in the MIRO. After all, it's only the weight of the caravan that he submitted for type approval, not that of the caravan in question. Different manufacturers have different ideas what to include in the MIRO. Basically, by definition, it's the minimum of equipment that would make the caravan saleable.
 
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I don't think that is correct regarding aquaroll as aquaroll is not a necessity. Allowance for gas bottle is normally up to 20kg. Wastemaster is inclusive if the caravan has an onboard tank, but not the piping. I don't think steps are part of the MIRO either?
I am basing my comments on what Swift advised me. The aquaroll was not included but as the caravan had an internal pump the water hose from some owner supplied external container was included. Had the caravan not had an internal pump then an external submersible pump would have been supplied and would be included in the MIRO. Swift advised that the supplied plastic steps were included in the MIRO. Mine also only included one 10kg gas cylinder, presumably a Calorlite. yours beinga larger caravan might well have had two cylinders include in MIRO.

What I have found was that since MIRO etc came into being there is no guarantee of conformity between makes in what is and what is not included in MIRO. Sometimes makers when asked the question by an Owner don't always give consistent information.

An earlier PC thread covers this subject.

 
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What I have found was that since MIRO etc came into being there is no guarantee of conformity between makes in what is and what is not included in MIRO. Sometimes makers when asked the question by an Owner don't always give consistent information.

There was never any intention in the formulation of the regulation to specify what is and what is not included in the MIRO. It only states that it should correspond to the weight of the caravan with the minimum of equipment to make the caravan saleable. It is up to the manufacturer to decide what that level of equipment is. It's entirely up to him. Consistency was never an objective.
I guess that if the manufacturer decided that heating was not absolutely necessary to make the caravan saleable and leave it up to the customer to order it as a factory fitted option, he could even leave heating off the MIRO.
 
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Using the mover correctly makes turning a TA a doddle even though you may need to shuffle. Shuffling causes less damage to the grass than a single axle being pivoted.
I have never owned a TA only SA. but I don't agree that a SA causes more damage than a TA. When I spin my SA on a sixpence, one wheel runs forward and the other in reverse, both wheels moving, no damage to the grass.

PS 2.5 pence to those born after 1972.
 
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The few people I talked to that have moved from SA to TA said it was nicer to tow. Then again they may have upgrade tow vehicles in process.
Having towed both single and twin axles with the same car I can say I did notice a difference. I suspect the twin axle design resists pitching while towing more than a single axle which gives the impression of improved stability.
 
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Both Trevermonty and Gary in the last two posts make relevant points.

As I think most of us know already, each time you change a caravan regardless of the number of axles, or it's size, it feels different to tow, and it takes some time to get used to the combinations nature. The differences may not always be huge.

Even if you don't change the caravan, just loading differently or fitting dampers can produce a change in the way it feels to tow.

In addition to using caravans for holidays, because of the work I did, I have towed many different mainly new caravans behind a wide range of different tow cars and vans, and from that experience I can say I prefer to tow longer caravans whether single or double axle.

The main difference I detected between SA & TA was how TA's would double tug the tow vehicle when each trailer wheel traversed a road imperfection or level crossing, and how they were less inclind to pitch so much under breaking. I can understand how such sensations may give a sense of stability.

I can also understand how the thought of having two axles can seem to offer a belief it must be better, and yes there can be an advantage if one tyre looses pressure the fact there's another on the same side is probably a good thing.

But overall I have not seen or experienced any evidence that having a twin axle endows better stability to car and caravan outfit.
 
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