Caravan rollovers

Whenarewethere · Guru

RE: Caravan rollovers

Eaglemax · Guru

So, it's quite clear, that many people believe high ground clearance can be a factor in roll overs or sway. Then what occurred in this country that saw so many to be THAT high? Braun? I mean unless you are going off road why such high ground clearance?. Caravans 50 years ago coped with aussie dirt roads and they were worse and more frequent than now. How many high up vans now go "off road". What is off road? Cant be too rough as owners would be gambling on damage to their rig. One apartment block passed me yesterday. Its roof had to be 3.2 metres off the ground plus aircon. My van roof height 2.2m was dwarfed. The other van had some sway but to be fair the side wind was strong....but it was still sway. Oh, it was on the Hume and yes, he was likely doing 110. Maybe I just don't get it?

Olive Oil · Senior Member

Eaglemax wrote:
So, it's quite clear, that many people believe high ground clearance can be a factor in roll overs or sway. Then what occurred in this country that saw so many to be THAT high? Braun? I mean unless you are going off road why such high ground clearance?. Caravans 50 years ago coped with aussie dirt roads and they were worse and more frequent than now. How many high up vans now go "off road". What is off road? Cant be too rough as owners would be gambling on damage to their rig. One apartment block passed me yesterday. Its roof had to be 3.2 metres off the ground plus aircon. My van roof height 2.2m was dwarfed. The other van had some sway but to be fair the side wind was strong....but it was still sway. Oh, it was on the Hume and yes, he was likely doing 110. Maybe I just don't get it?

The majority of high ground clearance, so called off road caravans, never leave the bitumen. blankstare

They do get washed & polished a lot though. biggrin

Come to think of it, I've never seen a dirty one in 8 years of traveling. confuse

Knight · Senior Member

F1 racing cars that were very close to the ground and had skirts around the sides to create a downwards suction effect were banned, they use air foils for downward force, as somebody jokingly suggest might be useful for high clearance caravans. The fact is that air foils do not work until the vehicle exceeds 200 kmh an engineer who designs variable rack and pinion steering systems for motor vehicle manufacturers told me.

However high ground clearance equals less stability which increases at higher the speeds. Obviously therefore maintaining safe caravan cruising speed of 80-90 kmh is recommended.

Aus-Kiwi · Guru

Really people !! We are making excuses for BAD driving . Nearly everyone Ive talked to over the years who has had crashes etc nearly all say it was driving unattention
!! Yes theres wind etc you have to be prepared for !! Plenty of other high vehicles out there !! Its mainly inexperience! I doubt too many ex truckies, semi drivers have this problem . Most the weight is around or just over chassis . The top half height has hardly
Any weight ., What some dont realise the DRIVER swinging on wheel just makes sway etc worse !! Pulling
In too sharp after passing a semi for example . The wind off semi plus turning in too hard exaggerates things . I tyre slightly down on air pressure ? Your in trouble !! No point blaming the van .! Blame the nut behind the wheel !! Its not F1 or racing . When they hook up 2 ton van to tow behind one then we can compare . Ground effects dont start working till 100 mph
anyway !

yobarr · Guru

Aus-Kiwi wrote:
Really people !! We are making excuses for BAD driving . Nearly everyone Ive talked to over the years who has had crashes etc nearly all say it was driving unattention
!! Yes theres wind etc you have to be prepared for !! Plenty of other high vehicles out there !! Its mainly inexperience! I doubt too many ex truckies, semi drivers have this problem . Most the weight is around or just over chassis . The top half height has hardly
Any weight ., What some dont realise the DRIVER swinging on wheel just makes sway etc worse !! Pulling
In too sharp after passing a semi for example . The wind off semi plus turning in too hard exaggerates things . I tyre slightly down on air pressure ? Your in trouble !! No point blaming the van .! Blame the nut behind the wheel !! Its not F1 or racing . When they hook up 2 ton van to tow behind one then we can compare . Ground effects dont start working till 100 mph
anyway !

Good post Graeme....lots of facts,logic and common sense! After my initial post,I have just been sitting here smiling at some of the ideas put forward! I am OK though because,after I removed the rooftop AC,my 3300kg van is only 2800mm high and super-safe! Cheers

SouthernComfort · Guru

Aus-Kiwi wrote:
Really people !! We are making excuses for BAD driving . Nearly everyone Ive talked to over the years who has had crashes etc nearly all say it was driving unattention
!! Yes theres wind etc you have to be prepared for !! Plenty of other high vehicles out there !! Its mainly inexperience! I doubt too many ex truckies, semi drivers have this problem . Most the weight is around or just over chassis . The top half height has hardly
Any weight ., What some dont realise the DRIVER swinging on wheel just makes sway etc worse !! Pulling
In too sharp after passing a semi for example . The wind off semi plus turning in too hard exaggerates things . I tyre slightly down on air pressure ? Your in trouble !! No point blaming the van .! Blame the nut behind the wheel !! Its not F1 or racing . When they hook up 2 ton van to tow behind one then we can compare . Ground effects dont start working till 100 mph
anyway !

Agree that bad driving including speed and inattention is the biggest contributor, but totally disagree with the rest of what you're saying. Combine the bad driving with an ungainly rig that should be back on the drawing board, and that's why the roll over's occur.

Can't compare a tug & van with a semi, totally different dynamics: Semi has wheels in each corner & a pivot point over or ahead of the rear axle. Ground effects(?) assume you mean clearance, starts working immediately and can be a hazard at real road speeds, forget 100mph. The high van body becomes a sail in cross winds, and with axle/s positioned amidships (whether single or dual), the thing pivots on it's wheels when under pressure, unlike a semi which comparatively speaking is virtually 'anchored' at its extremities.

It's a combo of all these things, why else is it that seemingly more high off-road vans roll over compared with other types? - arguably all van types can have bad drivers. I think you misunderstood the references to F1 cars. The example serves to illustrate the opposite characteristics of high vans - i.e. the lower the van, the lower the CG, less of a 'sail' for the wind to grab etc. the more stable it will be before the driver gets in the tug and adds his/her 'contribution'.

Aus-Kiwi · Guru

As long as we know and realise the difference. From what I see . Some towing vans seem to think its a race . To come upon them down the road . Can go on about all the theories! You STILL have to drive to your vehicles capabilitys. No point going on about F1 or semis . To some this is the first time they have driven or towed anything ..

Olive Oil · Senior Member

www.adelaidenow.com.au/news/south-australia/south-australian-couple-survive-caravan-rollover-caught-on-video/news-story/cd0161d09e04ffa23dc7758910b70890

Another one bites the dust.

-- Edited by Olive Oil on Tuesday 13th of August 2019 07:54:00 PM

Long Weekend · Guru

Like the first two mentioned earlier you can see the wobble beginning as the van passes.

As the camera vehicle and one seen in front are more than likely doing the speed limit, make you wonder why the caravan had to pass at high speed.

Murray

Eaglemax · Guru

Murray, thats speculation. Unless evidence, facts are known of a vehicles speed then guessing shouldnt come into it.

Long Weekend · Guru

True, it is an assumption that the two vehicles in the left lane are likely to be doing the speed limit.

But the wobble can clearly be seen as the van passes the camera.

Just to add another puzzle - they had left South Australia and the crash happened in the northern part of Queensland. That means that the driver had travelled a lot of road miles which you would think that they would have been reasonably familiar with towing by that time.

Murray

-- Edited by Long Weekend on Wednesday 14th of August 2019 01:31:35 PM

yobarr · Guru

Long Weekend wrote:
Like the first two mentioned earlier you can see the wobble beginning as the van passes.
As the camera vehicle and one seen in front are more than likely doing the speed limit, make you wonder why the caravan had to pass at high speed.
Murray

I am with you on this one Murray.Given that the road is straight,flat and dry,it is likely that traffic was travelling at (or above?) the legal speed limit,particularly the truck ahead.What I did find interesting was the way that the car got thrown around by the van. Perhaps he had not heard that the weight on the wheels of the van should be at least 10% less than the weight on the wheels of the car if safety is of any concern.Collyn Rivers,a noted authority on this subject,and an author of many books,suggests that that figure should in fact be 20%....with my present van,I run with the car having 21% more weight on its wheels than does the van.Helps prevent the tail wagging the dog,which was the situation shown in the video.Cheers.

-- Edited by yobarr on Wednesday 14th of August 2019 03:31:00 PM

boab · Senior Member

why would you want the van to be heavier than the tug sounds stupid to me

SouthernComfort · Guru

Yobarr, I'm sure it's a just a typo, but you've contradicted yourself. Have another read.

Greg 1 · Guru

It depends a lot on the rig as several have suggested. I have towed vans that quite frankly were dangerous above 80kph. (One that I hired once). At 85 it would sway alarmingly and despite my best efforts at redistributing weight about the van, it made little difference. I was very happy to hand the thing back to the owner. My current rig will sit happily at 100kph without a twitch provided that conditions permit. The trick is being bright enough to recognise when they don't and reduce the speed accordingly. Passing other traffic can be done safely provided you are aware of the aerodynamic forces at play with some major interference to those from the other vehicle if its of any size, and understanding what effects that will have on your rig so that you are prepared for it and can adjust accordingly. All imputs to steering, throttle and braking should be as smooth as physically possible and steering imputs kept small as possible. It is much like driving a race car at speed. It demands concentration and some modicum of skill, which unfortunately some are sadly lacking.

Eaglemax · Guru

So, the road is straight and good surface-conclsion by some- the camera car and the one in front likely doing the speed limit....gee I'd hate for you guys to be my lawyer! Both those vehicles vould be doing 85kph and the passing vehicle 100. Where is your proof that was not the case? Yobarr where is your proof the tug and caravan weights werent spot on? What if the accident car had a blow out, driver had a dizzy spell or cross wind contributed? Sorry, your assumptions make you armchair experts.

yobarr · Guru

SouthernComfort wrote:
Yobarr, I'm sure it's a just a typo, but you've contradicted yourself. Have another read.

Thanks Tony....trying to do too many things at once,and no proof-reader! Cheers.

yobarr · Guru

Eaglemax wrote:
So, the road is straight and good surface-conclsion by some- the camera car and the one in front likely doing the speed limit....gee I'd hate for you guys to be my lawyer! Both those vehicles vould be doing 85kph and the passing vehicle 100. Where is your proof that was not the case? Yobarr where is your proof the tug and caravan weights werent spot on? What if the accident car had a blow out, driver had a dizzy spell or cross wind contributed? Sorry, your assumptions make you armchair experts.

You are right! After viewing this video many times,trying to determine possible causes for this incident,I have concluded that not only was the driver speeding,but both front tyres blew out at the same time,cross winds had unsettled the van,and the driver had a dizzy spell when he bent down to retrieve the stubbie he had just dropped. And the fact that the car was thrown around by the van would suggest that the car was the lighter of the two vehicles......tail wagging the dog comes to mind.After driving B-Doubles,semis and many other vehicles over millions of kilometres,in many countries,I can assure you that the chances of two vehicles travelling 15km/hr below the speed limit,on a flat,straight and dry bitumen road,in fine weather and with little traffic,are virtually nil.Safe and happy travels to all.Cheers

P.S Was the tow vehicle not a Pajero? If so,when the van has an ATM above 2500kg,the maximum towball weight drops to only 180kg.This means that when a Pajero is towing a van with an ATM of 3000kg,the ball weight is a ridiculously low 6% .......stupidity in the extreme.And people wonder why their vans fall over! Spare me.

-- Edited by yobarr on Wednesday 14th of August 2019 02:51:16 PM

SouthernComfort · Guru

Greg 1 wrote:
It depends a lot on the rig as several have suggested. I have towed vans that quite frankly were dangerous above 80kph. (One that I hired once). At 85 it would sway alarmingly and despite my best efforts at redistributing weight about the van, it made little difference. I was very happy to hand the thing back to the owner. My current rig will sit happily at 100kph without a twitch provided that conditions permit. The trick is being bright enough to recognise when they don't and reduce the speed accordingly. Passing other traffic can be done safely provided you are aware of the aerodynamic forces at play with some major interference to those from the other vehicle if its of any size, and understanding what effects that will have on your rig so that you are prepared for it and can adjust accordingly. All imputs to steering, throttle and braking should be as smooth as physically possible and steering imputs kept small as possible. It is much like driving a race car at speed. It demands concentration and some modicum of skill, which unfortunately some are sadly lacking.

All very sound logic Greg. Also have to say you're a brave man for daring to mention racing cars , I mentioned it once and thought I'd got away with it, but alas the analogy in my case was well and truly lost on some folks it seems...

Long Weekend · Guru

This is starting to get a bit argumentative! As for me I'll make this my last comment on the matter.

Regarding Eaglemax's comment "What if the accident car had a blow out, driver had a dizzy spell or cross wind contributed?" In this specific instance the dash cam clearly shows the van wobbling as it passes the camera vehicle so it looks like the first two can be ruled out. Granted, a cross wind might have had an effect, I didn't analyse the video that thoroughly for moving tree branches.

Strangely, they left South Australia and the accident happened in northern Queensland - that gives them a lot of road miles travelled. One would have thought that would have given the driver considerable experience!

Murray

Eaglemax · Guru

Long Weekend wrote:
This is starting to get a bit argumentative! As for me I'll make this my last comment on the matter.

Regarding Eaglemax's comment "What if the accident car had a blow out, driver had a dizzy spell or cross wind contributed?" In this specific instance the dash cam clearly shows the van wobbling as it passes the camera vehicle so it looks like the first two can be ruled out. Granted, a cross wind might have had an effect, I didn't analyse the video that thoroughly for moving tree branches.

Strangely, they left South Australia and the accident happened in northern Queensland - that gives them a lot of road miles travelled. One would have thought that would have given the driver considerable experience!

Murray

Murray, I don't see this as an argument just disagreement. You might well be correct but I use caution when it comes to the poor guy that had the accident. I just want to support a rig owner if he was in fact doing everything legally.

Yobarr, your experience is vast no doubt, but others have experience vast in other fields. Mine is law enforcement and investigations. I don't like speculating. For example you hammer home the point of axle weights and the "tail wagging the dog" but you could be wrong in this case. Some facts are-

https://www.mitsubishi-motors.com.au/vehicles/pajero/specifications/m1/NX8W46

Kerb mass (kg)

2302

Gross Vehicle Mass (GVM) - [kg]

3030

Gross Combination Mass (GCM) - [kg]

6030

Maximum payload (kg)

728

Maximum front axle load (kg)

1330

Maximum rear axle load (kg)

1780

Towing capacity - braked (kg)

3000

Towing capacity - unbraked (kg)

750

Towing capacity - maximum towball load (kg)

180/250

Maximum roof load (kg)

100

The caravan Kingdom around 20ft

https://www.caravancampingsales.com.au/items/details/2014-kingdom-kensignton-evo/OAG-AD-17453283/?Cr=5

ATM around 2480kg if 21ft then around 2590kg.

Towball Pagero is 250kg. Mitsubishi state the car can tow up to 3000kg which would be well below the 10% point, the company also say a towball weight between 6-10% is acceptable !! which obviously isn't.

However for this case we must assume the owner didn't exceed around 2500kg ATM and if he/she did it wasn't by much. That means had the owners loaded up the tug with 2 persons and say 150kg of fuel and luggage the travelling weight total for the tug would be equal to or over the ATM of the caravan....not "wagging the dog" Yobarr.

So looking at the vid many times I speed could be a factor but the two vehicles on the left hand side did not look like they were doing 100kph, maybe 90 or so. The Pagero looked like it was doing 20-25kph faster judging by the rapid overtaking so say 110kph. Would 10kph too fast cause the crash- possible. But the sway initiated during the overtaking maneuver likely from the two rigs side by side which we have all experienced. Add that to high C of G, possible empty water tanks reducing its normal towball weight and bit of weight on the rear bumper all contribute.

However, the Pagero owner quite possibly had everything legal with his set up. Happy to be proven otherwise and figures scrutinized.

Tony

blaze · Guru

thanks tony, that's been the best post in this thread
cheers
blaze

Aus-Kiwi · Guru

I sense a little anxiety for the van driver ? As hes passing in the right lane . Seems the wind off truck and turning ever so slightly left adding to effect . Id say he just finally wanted to pass . Not concentrating on the situation !! Again you cannot drive like that when towing .,like to know his experience? Driving 2 or 3000 ks doesnt exactly make you experienced !!

montie · Guru

All pure speculation!

Nobody can possibly tell by viewing a video what could have possibly caused that accident.

The best any vanner can do when towing a van is make every effort to minimise the possibility by ensuring the tug weighs 10% at least more than the van, tug towing capacity is well within limits, 10% ball download, ESC fitted to van, don't speed and make sure your towing skills are up to scratch.

Even after you've done all that an accident can still happen but you can only minimise the risk.

Baz421 · Guru

Colin Penrose wrote:
Hi all. This is just my observation but I thought that I would put it out there. I have been taking an extra close look at all the caravan rollovers over the past year or two. I think all of them look like tandem off road vans of over 20 in length. Which brings me to think that there is either a problem with these huge heavy vans or a problem with the way they are being towed ???? The last one was obviously a very large van and once it started swaying the poor people had no hope stopping it. I dont Know the answer but I am just putting it out there. I pull a 16 pop top and so far I have never had a sway or anything untoward. I do always drive to the conditions but some of these rollovers seam to be on straight roads in good weather.
Just a thought to start, hopefully, a respectful discussion. Any useful suggestions for how to tow these very large vans.
Cheers Col

Hi Colin

have a look at axle location on bigger vans 22ft plus to keep ball weight down.

I don't know how they keep em on the road sometimes.

Baz

montie · Guru

Baz421 wrote:
Colin Penrose wrote:
Hi all. This is just my observation but I thought that I would put it out there. I have been taking an extra close look at all the caravan rollovers over the past year or two. I think all of them look like tandem off road vans of over 20 in length. Which brings me to think that there is either a problem with these huge heavy vans or a problem with the way they are being towed ???? The last one was obviously a very large van and once it started swaying the poor people had no hope stopping it. I dont Know the answer but I am just putting it out there. I pull a 16 pop top and so far I have never had a sway or anything untoward. I do always drive to the conditions but some of these rollovers seam to be on straight roads in good weather.
Just a thought to start, hopefully, a respectful discussion. Any useful suggestions for how to tow these very large vans.
Cheers Col
Hi Colin
have a look at axle location on bigger vans 22ft plus to keep ball weight down.
I don't know how they keep em on the road sometimes.
Baz

Colin,

I think we have two problems with heavy vans.

Firstly tug manufacturer's over stating the towing capabilities of their vehicles..ie tugs with a rated GCM of 6 tonnes being marketed to tow 3.5 tonnes. I believe that the very maximum that should be towed by these units is 3.2 tonnes preferably less.

Then we have the issue of tug/van weight ratio where many loaded heavy vans weigh substantially more than the tug and that is not ideal. I believe the tug GVM should exceed the van ATM by at least 10%.

Eaglemax · Guru

www.youtube.com/watch

in case no one has seen this sway simulator
Tony

SouthernComfort · Guru

Eaglemax wrote:
www.youtube.com/watch

in case no one has seen this sway simulator
Tony

My van is stored at Hardings Swift and I saw that demo at one of their open days a few years back. This vid and lots of similar ones have done the rounds, but it's still the most poignant demo that rams the load balancing message home.

iana · Guru

I looked at caravan roll-overs on U-tube, of those in Aust. all except one was single axle, one was a pop top, non were high off road machines, and all looked like they had leaf spring suspension. There were some huge vans doing waltzes across the road in the States, which of course would have had 15% ball weight.