Sitting here watching vans arrive on site most of which are twice the length as ours. My wife asked the question, why do some have twin axles and others single when they appear to be roughly the same length.
So, why?
So, why?
Why do some vans have twin axles and others single?
- Thread starter Sam Vimes
- Start date
In my view, twins will always be inherently safer to tow, more stable, and secure if there is a blowout. But I have never had one or towed one.
However, you will pay a premium on new, and maintenance and a lot more difficult to maneuver.
Improvements in tyres and chassis have allowed for ever bigger single-axle units. But overall it is probably a cost-saving for most of us to go for a single axle. Either on behalf of the customer and/or the manufacturer.
John
However, you will pay a premium on new, and maintenance and a lot more difficult to maneuver.
Improvements in tyres and chassis have allowed for ever bigger single-axle units. But overall it is probably a cost-saving for most of us to go for a single axle. Either on behalf of the customer and/or the manufacturer.
John
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It's easy to assume that bigger caravans may need a second axle to carry the extra size and weight of a bigger caravan, well that can't be true as some of the largest caravans only have single axles.
So it seems it's more likely to be a marketing decision rather than a mechanical one. Having TA sort of implies the caravan may be higher specification and thus appeal to the luxury orientated customer with bigger pockets. "look my caravan is better than yours"...
If there is any mechanical difference it probably is it's towing characteristics which empirically suggests it might have greater resistance to snaking, but I have seen plenty of pictures of TA's that have been involved in incidents so they are not immune instability, but it could equally be drivers usually in big 4 X 4's who don't think 60mph is fast enough.
What is definitely more difficult is manoeuvring the unhitched caravan, They are almost impossible to turn by hand, and even with a caravan mover they are still not as simple as a SA.
So it seems it's more likely to be a marketing decision rather than a mechanical one. Having TA sort of implies the caravan may be higher specification and thus appeal to the luxury orientated customer with bigger pockets. "look my caravan is better than yours"...
If there is any mechanical difference it probably is it's towing characteristics which empirically suggests it might have greater resistance to snaking, but I have seen plenty of pictures of TA's that have been involved in incidents so they are not immune instability, but it could equally be drivers usually in big 4 X 4's who don't think 60mph is fast enough.
What is definitely more difficult is manoeuvring the unhitched caravan, They are almost impossible to turn by hand, and even with a caravan mover they are still not as simple as a SA.
I'd agree with the previous comment regarding manoeuvring a twin axle by hand, I have few twin axle trailers, the only way to manoeuvre them by hand, is by cranking the jockey wheel right up, so that only the rear axle tyres are still in contact with the ground, I have gone though countless jockey wheel tyres! so when I recently bought my first caravan, it was a single axle by choice.
Had a couple of twin axles in the past, but I've stuck to single axle on our last few caravans
Why, for me a single axle caravan is
Horses for courses obviously
I wouldn't be averse to another twin, if it had a layout I liked.
Why, for me a single axle caravan is
- Easier to manoeuvre
- Cheaper to insure
- Cheaper to store
- Cheaper to service
- Less tyres to replace
- Motor movers are cheaper / not a compromise
- One less wheel lock required
- Simpler to level
- And i did once come across a site that didn't allow twin axles, even after speaking to them on the phone, which annoyed me somewhat
Horses for courses obviously
I wouldn't be averse to another twin, if it had a layout I liked.
We had a twin axle Sprite Quattro EB from 2018 to 2022. It was a much smoother ride towing it compared to the single axles previously and the one we have now. Manoeuvring one without a mover would be tough (assuming it couldn’t be done with the car). We loved the layout and the space and the low weight (not all twin axles are heavy), but it’s size (and the second axle) made smaller sites and pitches a bit of a challenge,
We had to manoeuvre caravans in and out of a test facility on an indoor flat painted concrete floor which required any caravan over 6M to be turned on its axis through 90degrees to position it in the test facility.
SA's were simple, but none of the TA's we tested would lift the leading roadwheels just by the jockey wheel being fully extended.
I remember Lunar launching a twin axle in the late 80’s where one of the axles could be raised to aid manoeuvrability. Never caught on though.
We have had twin axles for the past 18 years and have never had any real problems manoeuvring the unit. As simple as manoeuvring a single axle.
I would think a twin is less likely to snake than a single axle and nose weight is not a big issue like a single axle. Many twins use normal car tyres and the tyres are easier to source. Another factor is that we like the room and the layout.
However it is the choice of the individual what they prefer.
I would think a twin is less likely to snake than a single axle and nose weight is not a big issue like a single axle. Many twins use normal car tyres and the tyres are easier to source. Another factor is that we like the room and the layout.
However it is the choice of the individual what they prefer.
We prefer to tow a single axle caravan whether it was a 2 berth or a 4 berth
When we went seasonal we had a twin axle L shape lounge because there was more room and easy access .
When we went seasonal we had a twin axle L shape lounge because there was more room and easy access .
When it comes to manoeuvring a caravan uncoupled from the tow vehicle either by hand or with caravan mover, TA's are always more difficult. They cannot turn "on a a sixpence" like SA. Even caravan movers have to compromise and shuffle to complete a sharp turn.
Nose load is just as important if not more so on a TA, as the twin suspensions compromise getting the nose load set correctly.
Thanks everyone for your replies. It doesn't seem that there's any specific rule that says when you get so big it must be a twin axle.
In general TA's are fitted to larger caravans, but that is a design choice by the manufacturer rather than a design necessity.
Bessacarr used to have some quite small models fitted with TA's, and yet there are many of the largest caravans ( especially continental producers) with only a single axle. The number of axles does not dictate the internal layout of caravans.
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.
On the majority of TA you cannot achieve the "correct" recommended 5% of MTPLM nose weight as the hitch is restricted to 100kg. On our Lunar the correct nose weight should have been about 120kg, but we were restricted by the maximum of 100kg. On our current caravan our ideal nose weight is 140kg for a comfortable tow.
I think Sam is bored with mundane talk and post questions for us to debate and make life interesting. LOL!
Hi ProfJohnL from my personal experience we found we had plenty of room in the front of our Elddis Crusader super sirocco twin axle L Shaped lounge and this had the room to get my wheelchair in and move around .
I am sure the Caravan manufacturers are fully aware of the nose load requirements and would not fit inappropriate coupling hitches to their vans.
If your referring to the S value for towing vehicles, again the manufacturers will have had to comply with the directives to obtain type approval. It is the owners responsibility to ensure the tow vehicle and trailer are adequately matched.
If you have been unable to set a 140kg nose load due to mechanical limitations, then how can you know 140kg is "ideal" ? Just assuming the upper limit value is "ideal" is not necessarily true.
It is enough for the nose load to prevent the outfit from becomming unstable.
The fact you have successfully towed with a 100kg nose load could suggest you don't need to go as high as 140kg.
If your referring to the S value for towing vehicles, again the manufacturers will have had to comply with the directives to obtain type approval. It is the owners responsibility to ensure the tow vehicle and trailer are adequately matched.
If you have been unable to set a 140kg nose load due to mechanical limitations, then how can you know 140kg is "ideal" ? Just assuming the upper limit value is "ideal" is not necessarily true.
It is enough for the nose load to prevent the outfit from becomming unstable.
The fact you have successfully towed with a 100kg nose load could suggest you don't need to go as high as 140kg.
That's great, but the point is the design of caravan that suits your needs does not have to be a TA, another model could offer the same layout and space but only be an SA
The size and layout is not directly linked to the number of axles or vice versa.
I do need to go as high as 145kg as 100kg is too low and the outfit becomes unstable. Our ALKO hitch is rated for up to 150kg and car is rated for 175kg. Our previous Lunar we were limited to 100kg although at 120kg they ride did feel more comfortable.
No not at all...quite interesting..I think Sam is bored with mundane talk and post questions for us to debate and make life interesting. LOL!
Never likely to be an issue for us.
Might be interesting to see a caravan with 4 wheels... 2 at front, two at the back. Someone will no doubt tell me why you can't 😉
Not sure the initial premise is true. The one make that does not use twin axles on their largest models is Adria, with one exception, but they do have a longer a frame. which it is suggested makes for better stability.
The need for a specific nose weight and stability concerns are all theoretical but using twin axles does look to improve stability which is important so is probably worthwhile in my view.
The need for a specific nose weight and stability concerns are all theoretical but using twin axles does look to improve stability which is important so is probably worthwhile in my view.
Weight probably as the caravan would then need some sort of steering for the wheels to follow the vehicle otherwise the front wheels will srub everytime you turn?
Well, not quite. 2000kg is about the limit for a single axle caravan. Anything above that and one does need a second axle. I don't know of any Continental manufacturer that makes a twin axle below 1900kg.
A four wheeled caravan which is not close coupled would require a steerable front axle, yes. If I recall correctly, it must also have an independent braking system, i.e. overrun braking is not allowed with such a configuration.
SA s served us well until15 years ago . The longer SA never gave cause for concern but the earlier 12 and 14 footers needed some extra care even when loaded correctly.
I prefer a TA
Feels very stable and less susceptible to large vehicle or sudden wind
At the time no British caravan of the size and layout was or even now is available.
The payload is generous.
The downside of moving as stated by others is frankly abysmal . Manhandling is a no go.
I use a mover on one axle. Quad movers eat into the payload. Four tyres four hub nuts etc costs more . Tyre pressures are much lower so you could argue less stress on the tyre. Get a blow out and you still have three tyres.
In fairness as and when we change the number of axles will not be a priority , more so the layout, functionality and reliability .
I prefer a TA
Feels very stable and less susceptible to large vehicle or sudden wind
At the time no British caravan of the size and layout was or even now is available.
The payload is generous.
The downside of moving as stated by others is frankly abysmal . Manhandling is a no go.
I use a mover on one axle. Quad movers eat into the payload. Four tyres four hub nuts etc costs more . Tyre pressures are much lower so you could argue less stress on the tyre. Get a blow out and you still have three tyres.
In fairness as and when we change the number of axles will not be a priority , more so the layout, functionality and reliability .
Back in the 70's one of the UK caravan manufacturers did have a a four wheel caravan with the forward axle having steering rather like the showmans caravans. Reversing is a real pain.
They never caught on.
They never caught on.
Lynton did a 4-wheel caravan like that in the '80s - it wasn't a commercial success. Australian road trains have trailers with that sort of layout although use more axles/wheels.
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