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

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.

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.

Shane

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?

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.

"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?

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.

"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..

Logical?

Safe Travels.

Cheers
Greg

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.

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. :-)
AlanH.

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!

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.

http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/vsb_06.aspx

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.