How top heavy are 4WD Motor Homes and are they safe?

Submitted: Thursday, Oct 03, 2013 at 15:18
ThreadID: 104576 Views:4467 Replies:10 FollowUps:11
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There was a bad accident this morning at Torbanlea south of Childers this morning involving a fair sized 4WD Motorhome and a Colorado. The Colorado came off second best and it was really lucky that no one was killed. I think I saw the MotorHome in Childers yesterday and it was pretty high.

Just wondering how safe they are in an emergency or whether they tend to tuck under and roll.

4WD Motor home rolls
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Reply By: Member - Chris_K - Thursday, Oct 03, 2013 at 16:03

Thursday, Oct 03, 2013 at 16:03
Hi Lyn

I've driven a few 4WD's that have a high centre of gravity...but not a Motorhome. In most instances they would be no more dangerous than other cars. It depends on the driver, road conditions, how the vehicle is maintained and how the vehicle is packed.

For any vehicle is it better to store heavy stuff down low, and high up - store light stuff. They will tend to sway and roll more - but then again if you want to carry everything with you, there are compromises - they just have to be driven as a 4WD Motorhome and not a sports car. A few years ago, there were multiple accidents on Fraser Island with backpackers and Troop Carriers...they stuck so much stuff on the roof, they were downright dangerous.

Don't know who was at fault - but as you say - lucky no one was killed.

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Follow Up By: Ron N - Thursday, Oct 03, 2013 at 16:23

Thursday, Oct 03, 2013 at 16:23
Chris has nailed all the points very well. We took a Maui Platinum River dual wheel motorhome from Perth to Darwin last Winter, covering well over 5000kms.

These units are 6 berth and based on the Mercedes Sprinter and VW Crafter vans/trucks. They're pretty high in relation to axle/chassis/spring width - and they're heavy. However, these vehicles do have good anti-roll technology in the form of sway bars and good suspension design.

I didn't come across any problems with handling or feelings of top-heaviness, any more than an average fully loaded truck.
You drive all commercial vehicles, as exactly that - you don't drive them like sports cars.

Keeping the heavy items down low is important with any vehicle, and more so with trailers and 'vans. Driving motorhomes with extra care in relation to stopping distances and distance between vehicles is nothing more than practising good driving skills.

I would hazard an educated guess that a Troopy with a high roof camper setup is more top heavy than one of the VW or Mercedes motor homes, because the Troopies are quite narrow in track, and high in relation to their track.
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Reply By: Ron N - Thursday, Oct 03, 2013 at 16:38

Thursday, Oct 03, 2013 at 16:38
I've just been examining the crash pics in detail, and it appears that that crashed motorhome is an old IH Metro delivery 'van that has been extensively modified and converted to 4WD with new axles front and rear.

It appears the axles installed under it are quite wide - but you'll notice that the chassis rails are quite narrow on the Inter.
This would be because the van was originally fitted with dual wheels. IH made several versions of the Metro van from 1965 to 1978, based on the C1300 and D1300 to C1600 and D1600 Inter truck chassis.
That motorhome looks like an accident waiting to happen, IMO, and it would be interesting to see whether an engineers report was ever done on the modifications - particularly the major increase in body height - and if any C of G calculations were ever done.

Those people in that Colorado need to go buy a Lotto ticket. I find it amazing anyone in the Colorado survived - and the accident result gives me a whole lot of new-found respect for Colorado body strength.
AnswerID: 519115

Follow Up By: scandal - Thursday, Oct 03, 2013 at 17:19

Thursday, Oct 03, 2013 at 17:19
Not a heavily modded metro van, it's a 4WD acco, it may have even been a bus at one stage, they where all this high.
It look's to me he has swerved and turned the steering at the same time, always gunna end bad in what is essentially a truck.
All the buses running Fraser don't have duals either, would NOT of help in this situation in whether it had dual's or not.

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Follow Up By: Ron N - Thursday, Oct 03, 2013 at 17:36

Thursday, Oct 03, 2013 at 17:36
Shane - Yeah, I can see now that it has an ACCO grille - but the ACCO's were all tilt cab?
Maybe this was a converted fire truck or some other specialised body?
Can't recall IH making a factory van body in the ACCO range.
4x4's were available in the truck models, with dual wheels, but I don't recall seeing a factory IH 4x4 with super singles all 'round?
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Follow Up By: Lyn W3 - Thursday, Oct 03, 2013 at 17:58

Thursday, Oct 03, 2013 at 17:58
I'm pretty certain its the one that has been around Childers for a while, it's an International but highly modified, probably and early model ACCO what we used to call a "Hot Box" with the motor between the seats, first time I saw it I thought it was a jumbo OKA. Think it had WA plates but not sure.
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Follow Up By: Notso - Thursday, Oct 03, 2013 at 20:03

Thursday, Oct 03, 2013 at 20:03
"It look's to me he has swerved and turned the steering at the same time, always gunna end bad in what is essentially a truck.

Did you mean Braked? It's be pretty hard to swerv without turning the steering wheel?
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Follow Up By: Ron N - Friday, Oct 04, 2013 at 00:01

Friday, Oct 04, 2013 at 00:01
Lyn W3 - The rolled motorhome has S.A. plates. I blew up the news site pics and the plates say "S.A. the Festival State" under the letters and numbers.

The skid marks pretty clearly indicate a total panic stop, with fully locked brakes every inch of the way.

Releasing the brakes if they lock up, is the only way to keep control. I'd have to say the driver of the motorhome is seriously lacking in vehicle control skills - and other driving skills as well.

QUOTE - "Mr Smith said he thought the mobile home may have skidded across the highway after stopping suddenly to avoid running into another car slowing for nearby roadworks." - UNQUOTE

If this witness statement is true, then the driver of the motor home is guilty of negligent driving.
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Reply By: Robin Miller - Thursday, Oct 03, 2013 at 16:59

Thursday, Oct 03, 2013 at 16:59
Prospective purchasers would be well advized to find out the tip over angle of any vehicle as a matter of urgency Lyn.

It is the single most dominate variable related to serious accidents, which is why I have always been concerned about it and would not buy some cars.

In many countries a "static stability factor " test as its known is required and results labelled on a car just like fuel use.

In Australia though its buyer beware.

Most never get a second chance at a roll-over.
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Follow Up By: The Explorer - Thursday, Oct 03, 2013 at 21:25

Thursday, Oct 03, 2013 at 21:25
"It is the single most dominate variable related to serious accident"

Maybe, but all the other less "dominant" variables add up to exceed serious injuries caused by roll overs ... so if you get over "concerned" about one single aspect (e.g. tip over angle) you could end up in a less safe car. An obsession with one technical specification has resulted in some people doing just that - they have purchased a specific car in preference to another thinking that a rollover is less likely (probably true)..but overall they are more likely to be seriously injured simply because in the more frequent type of accidents, not involving a roll over, which results in the bulk of injuries (i.e greater than 50%), they are MORE likely to be seriously injured.

This also translates to the rollover - while they may be less likely to roll over by some unknown factor (its not just the technical specification of a car that determines if it will happen) they are more likely to be seriously injured when it does happen because the car lacks safety features found in cars more likely (theoretically) to roll over.

Which is not to say it is a factor that should not be considered..


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Follow Up By: Robin Miller - Friday, Oct 04, 2013 at 07:44

Friday, Oct 04, 2013 at 07:44
Hi Greg

I think we basically agree on that point.
While it makes little difference at low speed 4wding, the outcome for cars fitted with stability controls and lots of air bags is a lot better than those earlier models of the same car without them.

While all our big touring wagons are now so fitted most of the commercial based vehicles are not and this along with SSF would be high on my list of things to be considered before purchase.

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Reply By: Herbal - Thursday, Oct 03, 2013 at 17:52

Thursday, Oct 03, 2013 at 17:52
Hi Lyn,

Your question is a good one...and all the answers given are very valid and very good.

At the end of the day, there is no single answer...NO vehicle is safe - if the nut holding the steering wheel is loose !!

There are a whole heap of rules and regs about vehicle limits. Size, shape, weight etc, etc. But at the end of the day it is ONLY as safe as the driver makes it !!!

The most important thing is DON'T PANIC...I have driven large vehicles for many years and had my fair share of scary things happen. A 5 tone truck doing 1 1/2 complete 360's at walking pace! Scares the hell out of ya... One just does not expect a truck to lose total traction at less than 10kph and go into a complete spin...but I am living proof that it can and does happen...Or a brand spanking new 8 toner at 20kph losing all brakes including maxi's at only 20kph in the middle of Sydney will make any mere mortal go looking for clean undies...I know cos mine needed changing afterwards !!! It is not just big things that cause problems !

The best advise that can be given...Go to school !! Find a driving school in your area that caters for large vehicles and trailers. It will be a few hundred bucks but your life is worth it ;) Don't find a "friend" you don't want their bad habits...go to school. Fork out the extra dollars and go for the heaviest licence you can afford. A HR might cost $1,000 or more in school fees...But it will make you feel quite safe driving a motorhome knowing that you have some basic skills to stay in control and not panic.
AnswerID: 519121

Follow Up By: AlanTH - Friday, Oct 04, 2013 at 09:00

Friday, Oct 04, 2013 at 09:00
I know what you mean Herbal as I've done a couple of slow 360s going down a wet ramp into a mine years ago. That was an Acco fitted out as a service truck and had shocking brakes (which didn't cause the problem) but luckily there was a bench I was able to run onto and stop before going over the side.
Did my laundry when I got back to the donga that night. :-)
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Reply By: Life Member TourBoy, Bundaberg - Thursday, Oct 03, 2013 at 19:06

Thursday, Oct 03, 2013 at 19:06
Any vehicle will roll going sideways down that embankment at speed. Lucky the acco has a flat body so it put pressure more evenly on the colorado and who knows maybe the crappy alloy roll bar actually absorbed some impact before being crushed. People need to be aware of their surroundings, there are a lot of roadworks around the area and built up traffic may have been a factor.
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Follow Up By: Ron N - Friday, Oct 04, 2013 at 00:05

Friday, Oct 04, 2013 at 00:05
LMT - Geez, that ACCO body is pretty impressive with its structural strength, eh?

Any other motorhome would be spread up the hwy in 1000 pieces after a rollover!

The rollover has hardly marked the body of the motorhome, and every item secured in, under and around the body, is still in place as well!
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Reply By: The Bantam - Thursday, Oct 03, 2013 at 22:18

Thursday, Oct 03, 2013 at 22:18
Do 4wd motorhomes have a high centre of gravity..... of course they do.

The same vehicle in a 4wd version will in general have a higher centre of gravity than the same vehicle in 2wd.....THEN people jack em up, which makes them worse.

The same vehicle fitted with a motorhome body will have a higher centre of gravity than one with a flat tray (or even a pantech body)...if the person building said camper body is not very carefull and the person who loads it likewise..the centre of gravity can end up very high.

If a 4wd is fitted a motorhome body it has the potential to have a very much higher centre of gravity than may would be expecting.

This will influence that vehicles ride, cornering and handling under brakes.

The above are unavoidable facts.

Are they safe.......compared to what.

They will not be "as safe" and as easy to drive as a passenger car.

Compared to a 4wd and trailer....well......any passenger car or light commercial towing a large high and long trailer on a single central axle group is fundamentally unstable.....witnessed to, by the need for all sorts of devices and modifications people find necessary to improve the stability of their rigs.

A properly designed motor home built on an adequate and suitable commercial vehicle base will be safer and easier to drive than an equavalent sized caravan towed by a 4wd......and it will probably be more capable off road.

It must be understood that while these commecial vehicles ( trucks) that they base these motorhomes on are specifically designed to carry load (and passenger cars are not), they are not subject to the same design rules and safety expectations as passenger cars and once fitted with the bodies they are not crash tested or road tested to the extent that passenger cars are.

Are they safe...well "safe" is a relative word.

Shall we break out the books and undertake a full risk assessment, complete with risk matrix?

AnswerID: 519138

Reply By: Bob Y. - Qld - Friday, Oct 04, 2013 at 11:30

Friday, Oct 04, 2013 at 11:30

Interesting thread, thankfully not a tragic one.

To answer your question, I would say these 4wd motorhomes are safe, as long as they are driven as such, a heavy, high COG vehicle, with adequate brakes, steering & suspension(dependant on degree of maintenance), when driven within its design parameters.

Judging by the photos in article, he was under heavy braking, and due to either steering, or brakes, has drifted off over the shoulder. Once the motorhome was no longer straight, to line of travel, then he's in trouble.

One could suggest that the driver wasn't paying attention, or driving too close to the vehicle in front, but as I wasn't there then it's anyone's guess.

On the stability of heavy vehicles, I've seen triple road trains(in early hours of morning) go through that big roundabout, in centre of Longreach, at speeds that would be equal to that of most cars and 4wds, using that intersection. Quite stable until they get onto the shoulder, and the COG changes position.

Hope the passengers of the dual cab make a speedy recovery,

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Reply By: Lyn W3 - Friday, Oct 04, 2013 at 12:39

Friday, Oct 04, 2013 at 12:39
Are there any regulations when building/converting a truck to a motor home. I am assuming it would need to pass the regular truck inspection but what about cabin modification, COG, load rating for roof rack etc etc.
AnswerID: 519166

Follow Up By: Ron N - Friday, Oct 04, 2013 at 14:14

Friday, Oct 04, 2013 at 14:14
Lyn - Modifications to vehicle design are controlled by the Federal DRID, via the Vehicle Standards Bulletins.

Each Bulletin covers a specific area and outlines any design changes to original manufacturers design, that are either allowed or dis-allowed.

Trucks are classed as vehicles over 4500kg GVM, and under that figure, vehicles are classed as passenger vehicles.

Different regulations apply to trucks, as compared to smaller vehicles, and the regulations are generally stricter for trucks, than they are for passenger vehicles.

Any changes to design are usually classed as minor or major. In general, minor changes that do not substantially affect the OEM design are allowable.

However, major design changes such as cabin re-construction, complete axle changes, body additions, major drivetrain changes, braking system alterations, steering modifications, along with many other major changes, all require an engineers supervision and a signed engineers certificate to be presented upon registration.

In recent years, authorities have been putting pressure on hotrodders and vehicle modifiers to try and stamp out "backyard 'rodders" from doing major modifications themselves, with little engineering input - and trying to move all modification work across to selected "professional" vehicle modification shops.

However, many people still carry out modifications in their own sheds and workshops - and sizeable numbers of these people are quite skilled.

The problems start when someone has good fabrication skills, but lacks professional engineering qualifications, so that potential un-recognised problems start to sneak in with their vehicle modifications.

Typical examples are wheels modified with increased offset and steering components modified by heating and welding.
Modified offset wheels seriously affect handling by extending the arc radius of the turning action of the front wheels.

This leads to increased loads on other steering and suspension components that can be outside manufacturers design limits.
Handling is affected with increased offset wheels, because the wheelbase is shortened substantially on one side, and lengthened substantially on the other side, when the steering wheel is turned a substantial amount.

Steering components must never be altered by heating or cutting without reference to the manufacturer, because most critical steering components are heat-treated - and any application of serious heat will affect the heat treatment and possibly cause embrittlement.

The major problem with all motorhome conversion "projects" is trying to keep the vehicle GVM within manufacturers and rego limits.

Many converted motorhomes are seriously overweight, and many easily tare out at 6 or 7 tonnes, when the original vehicle GVM is much lower.

I'm sure a lot of converted motorhome owners weigh their vehicle with nothing in it for rego purposes - then they go back home, fill it up with several hundred litres of fuel and water, heavy gas bottles, food supplies and dozens of household items (including heavy crockery) - and then they suddenly find the tare is now a tonne and a half more, than what is on the rego papers.

Add in the extra height of a 4WD vehicle body, and you've got potential C of G problems with all that extra weight.
Add in a driver lacking vehicle handling skills, and you have an accident looking for a place to happen.

Cheers - Ron.
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Reply By: mikehzz - Saturday, Oct 05, 2013 at 06:39

Saturday, Oct 05, 2013 at 06:39
They can't be much more top heavy than this... :-)
AnswerID: 519204

Reply By: Bandicoot - Sunday, Oct 06, 2013 at 21:55

Sunday, Oct 06, 2013 at 21:55
We have an EarthCruiser and it has an excellent (low) COG. I think a key issue is whether the "4WD motorhome" is a rigid-sided camper or pop-top. If it is a rigid sidewall camper, then it has heavier and taller sides, and these types always seems to have serious internal "overhead lockers". The lockers will be full of gear, of course. Often rigid body 4WD motorhomes also seem to have roof racks as well e.g. for firewood.
The EC is a pop-top so has "canvas" sides for the top 1 m, no overhead lockers and no roof rack. When the roof is lowered, it is the same height as the cabin. The walls are fibreglass and the camper is actually quite light. The downside to this is that this means we need to be careful with not taking unnecessary gear to store!
A major issue with all the 4WD chassis that are used to create 4WD motorhomes, SFAIK, is that they have drum brakes. In some cases (such as the Canter) these are not "self-adjusting" either, and when non-self-adjusting drum brakes are combined with super singles (larger diameter wheels), the braking is marginal at best.
AnswerID: 519295

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