An interesting observation post is alongside a busy boat ramp where a majority of weekend fishermen struggle to launch and retrieve their boats, after battling the vehicle steering wheel to reverse down the boat ramp.

ROLL CENTRE

www.exploroz.com/Vehicle/Caravans/Caravan_Dynamics.aspx

I have just read the article, (by Collyn Rivers), put up by Peter (Peter n Margaret)

https://www.rvbooks.com.au/page/why-caravans-sway/

I take note (if I had read it correctly), that Collyn Rivers says that over 250 caravans overturned in the first six month of 2018

He then goes on to say that excess speed is always a major factor

I take this as coming from the horses mouth

It would still be handy to know, if certain brands/sizes/weights/heights of caravans, are more easily overturned

Knight wrote:

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ROLL CENTRE

www.exploroz.com/Vehicle/Caravans/Caravan_Dynamics.aspx

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 And it describes why the typical caravan independent suspension that is becoming fashionable, is about the worst choice available in terms of caravan stability.

There is certainly a need to improve the terrible leaf spring suspensions traditionally fitted to caravans, but independent suspension is not the way to address that, in my view. It is better addressed by using decent, longer travel leaf springs which are simple, rugged and cheap.

Independent suspension itself does nothing of value for a caravan. Problem is that those who have it love it but that is because they compare it to about the worst leaf spring designs available.

Cheers,

Peter

Knight wrote:

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Colin Penrose wrote:

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That is what I thought.  If you have a lot of clearance underneath the wind can lift the van more easily ???

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 The greater the ground clearance the poorer the road holding worsening the higher the speed.

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My view exactly. Higher ground clearance = higher overall height = higher centre of gravity = less stability. Entirely logical when you consider that F1 racing cars are the polar opposite, designed with minimal ground clearance and CG for maximum stability at hyper speeds and maneouvers.

Heavy full height o/r vans are about as aerodynamically inefficient as it gets. I reckon the only answer is to finely tune the load balance (vertical and horizontal) and travel at much lower speeds. Adding wings and other band aids (ESC excepted) will not compensate.

Aus-Kiwi wrote:

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Yes . Fitting shocks PROPERLY to leaf suspension also . Should be fitted but everythings built to price !!

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 Dampers are a very valuable addition to leaf spring suspensions but are absolutely essential for coils, parabolic leaves and torsion bars which have zero self damping and will go "out of control" if the dampers fail and they are more likely to do so because of the much higher work load they have on those spring designs.

Cheers,

Peter

I have Dutch friends who have this 10m caravan (32feet?) and they tow it at speeds up to 130kph behind their Porsche.
German built. Its total weight on the road is about 2.5T
10% ball weight? I don't think so!

Cheers,

Peter

Plain Truth wrote:

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Where is his tow ball ? 

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 Good question.

There is a button in the boot...

Cheers,

Peter

There are some short videos clips on these & it would bring tears to your eyes to say the least! Land Rover have them as well.

Discovery Sports motorised tow bar:

https://m.youtube.com/watch?v=KTbJjZvq5jE

-- Edited by Whenarewethere on Sunday 11th of August 2019 08:20:21 PM

High clearance... is great... when you need to get under your van to do something. Independant suspension is great.... when you need to move forward or backwards whilst under your high clearance van doing something.

Towing a van at 130kph in Australia...  well.... good luck with that says the roo, emu, eagle with a full belly etc.

-- Edited by Noelpolar on Sunday 11th of August 2019 09:11:18 PM

-- Edited by Noelpolar on Sunday 11th of August 2019 09:14:26 PM

Well our van is 8.8 meters long, and has been made with, according to the experts on here, everything wrong. We have thousands of K's left to travel, but according to these posts we won't make it. But we travel slowly and rarely pass vehicles. Only done about 20,000km so far and it tows perfectly, never had a severe wobble, and any effect felt is from a side wind. So you had better say a prayer for us.
But speed and impatience I think are the dominating factors, followed by those who mount huge loads at the extremities.
I saw one that had so much on the back he had a crane mounted there as well, others three spares, water and fuel, they all passed me going flat out.

iana wrote:

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 Only done about 20,000km so far and it tows perfectly, never had a severe wobble, and any effect felt is from a side wind.

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 That rarely understood by caravan owners is that their rig may feel ultra-stable in normal driving.

https://www.rvbooks.com.au/page/why-caravans-sway/

Cheers,

Peter

In my humble opinion, many road accidents, including those involving caravans, are caused by stupidity which is manifested in many ways. The principle of driving within the limits dictated by experience, road conditions and vehicle capability seems to either be unrecognized or ignored by people sometimes, causing them to exceed one or all of the safety limitations. Towing a 12 month old caravan with ESC and sitting on what I consider to be a safe highway speed of 90kms/h we are often passed by other vehicles towing vans at what must be well over the speed limit, some of which appear to be too heavy for the towing vehicle. It's all very well to be charging along at high speed or with an overloaded van UNTIL something goes wrong and then it's usually too late, sometimes leading to tragedy. For instance, recently people were killed in a caravan rollover involving a 120 series Prado tow vehicle. 120 Prados have a maximum allowable towing capacity of 2.5 tonnes and weigh 2.6 tonnes, makes sense, so Prado plus van 5.1 tonnes max. The police collected everything from this particular accident and put it on a weighbridge. I live near where that accident occurred and I was told by a person who I believe knows the facts that the total weight was in excess of 7 tonnes and the driver now faces several very serious charges. Whether this was ignorance or blatant disobedience of the parameters, people lost their lives and others will probably never recover from a horrendous event.
When people talk about driving courses for caravan owners I believe those courses should focus on the technical aspects of loading the caravan safely, towing speeds, reading road conditions,the ratio of van to tow vehicle including the results of using weight distribution hitches as a band aid solution to an incorrectly set up rig, in other words, avoiding getting into trouble rather than getting out of it. Drivers who have never encountered an emergency situation can live in a dream world where they imagine they can skillfully operate their vehicle to save the day when, believe me, when the crap hits the fan it's a lot more difficult than they can ever imagine. The table below gives the time in minutes taken to cover distances in kms at 80,90,100 and 110ks/h. Sure, over a journey of 300ks you save an 27 minutes by travelling at 120ks/h instead of 90 BUT the exponential increase in danger level you would think would not be worth the risk. Still...............you see it. Anyway, food for thought.

Distance travelled Time to arrive 80ks Time to arrive 90ks Time to arrive 100ks Time to arrive 110ks
100 75.00 66.67 60.00 54.55
200 150.00 133.33 120.00 109.09
300 225.00 200.00 180.00 163.64
400 300.00 266.67 240.00 218.18
500 375.00 333.33 300.00 272.73
600 450.00 400.00 360.00 327.27

Noelpolar wrote:

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High clearance... is great... when you need to get under your van to do something. Independant suspension is great.... when you need to move forward or backwards whilst under your high clearance van doing something.

Towing a van at 130kph in Australia...  well.... good luck with that says the roo, emu, eagle with a full belly etc.

-- Edited by Noelpolar on Sunday 11th of August 2019 09:11:18 PM

-- Edited by Noelpolar on Sunday 11th of August 2019 09:14:26 PM

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True. Can't compare European conditions with ours. Apart from the wildlife, Euro roads are much better surfaced, even in country areas. Fewer bumps or pot holes and the absence of soft shoulders also create less hazard. Also notice that most Euro vans (even full height ones) have a low centre of gravity, they're very low slung as well as lighter weight. The only times they can tow at 130kph plus is on motorways where keeping up with inherently fast traffic is a matter of survival. Still, I wouldn't want to tow at that speed. I've driven over there many times (not towing) and learnt quickly that on motorways your speed has to be increased to equal that of the next lane before you change, otherwise they're glued to your arse with headlights flashing in an instant. If towing I'd sooner stay planted in the inside lane! The other thing you never see in Europe is the likes of our ungainly high riding off-road vans.