Rollovers - what causes them?

I have been in a 2wd that rolled. it was a result of a front tyre blowing out. I was in the back of the panelvan and it looked like someone had just reefed the wheel to the left. Vehicle slid sideways and flat tyre dug into the bank sending us over and over and over - longest 3 seconds of my life bouncing around with tool boxes, spare tyres, esky, guns etc etc like on spin cycle

In my experience they result from the attempt at recovery from an unplanned deviation.

Through fatigue, looking down to change a CD or similar, spilt drink, phone use, dodge something on road etc. the driver swerves to recover. If they've ended up in the oncoming lane the accident is usually a head on or a glancing blow if there is one at all. Often it only results in a near miss.

The most common cause of the rollover is where the driver ends up in the gravel on the verge and is partially sideways as a result of a violent attempt to correct their path. As soon as they get grip or shortly afterwards the vehicle tips over. Often they manage to hold it until they get to the gravel on the opposite side but a subsequent correction there ends up in the same problem.

It's not a problem isolated to fourwheel drives. The same happens to people movers and vans, and even often to family sedans & wagons.

I've been to lots of em.

Dave

Easily done on greasy muddy roads.

I know of one instance with a well set up standard vehicle with 4wd engaged, travelling at a cautious 40kph on a wet greasy outback track, hit the edge of a wombat hole, and the vehicle slid sideways, lost traction, and a rear tyre popped off a rim and it slowly went over on its side.

Another instance where a driver sliding on Sliver City Highway in the wet did something similar.

Cheers
Phil

Had a mate roll over while stationary.

He pulled up on the side of the road to help another driver with a flat. The edge was wet and gave way under the vehicle and it slowly fell over while the vehicle was staionary. No one was in it as they were out fixing the other vehicle's flat.

He is very cautious where he pulls up now. (It happened up Darwin way in the wet)

How about due to excessive lifts & "temporarily" disconnected sway bars??

G'day Guys,

Word should be Crash instead of Accident, most tend to happen on straight roads due to a combination of things such as lack of concentration. This might lead to sudden over correction or too much speed. So many other factors, poor inflation, poor suspenstion. The list goes on, How many out their have driven along and suddenly found themselves crossing the centre line and then correct themselves. Lots of factors but most is probably a combination.
On another note, how many of you have cargo barriers or secure your stuff in the vehicle. I have attended hundreds of accidents and it is of concern how many thing inside your car can contribute to injuires even at low speed.

Jake

Several reasons or a combination.

High centre of gravity combined with a sudden swerve

High centre of gravity combined with a swerve + low tyre pressure

Etc. etc. etc.

Troopy + backpackers

Greetings

Basically for a vehicle to roll it needs to "trip". This usually occurs when a tyre deflates (more so with a front deflation) and the rim is able to dig into the surface in combination with a small lateral movement, causing the vehicle to "trip" (roll).

Front tyre deflation usually results in a tyre and rim separation combined with a wobbling of the wheel with the deflated tyre causing a turning action digging in the rim and causing the vehicle to "trip" (roll over)..

Firm grip on the steering wheel, stay away from the brakes, do not turn in the direction of the deflated tyre and no sudden deceleration. Adding power can enhance stability.

All of this is of course difficult to do when that front tyre suddenly deflates. Mostly the vehicle rolls.

Seatbelts, air bags and stronger modern vehicle structures make this type of accident more survivable providing, no solid objects are hit and the initial speed is not to high.

The higher the centre of gravity (CG) the easier this occurs. Hence 4WD's poor role over stats. Heavily ladden roof racks and overly high suspension lifts make this worse, causing big shifts in CG in an upwards direction.

Paul

Just another factor that contributes is when a load can move.

So with a large water or fuel tank, the fuel and water can slosh over to the downside, increasing the likelihood of rolling - naturally more likely the higher up it is.

And unsecured stuff on the roofrack can slide sideways having the same effect.

Cheers
phil

I'm surprised no one has mentioned wheel tracks, as a cause of roll-overs.

Dried wheel tracks, from previous wet weather events, have the potential to cause plenty of r'overs, if drivers suddenly drop a wheel into them. As mentioned above, the cause is probably blamed on tyre faults, after the event.

The addition of power steering, to modern 4wds, has probably saved a lot of people the hassles of a rollover.

Hooroo...

If you drive your softroader or 4WD like a car then you are very likely to have a rollover, especially if it is carrying more weight (incl passengers).

It is easy to oversteer in an apparently nimble softroader and it does not require a sudden tyre deflation to tip over. Most cars will weather over-correction or sudden direction change but specialist vehicles are not nade for that.

Quite apart frrom all of that, many the design requirements for off-road are contrary to those for stability and handling at speed.

Lesson: drive the fourby as a fourby - be more cautious of its limitations.

How long can car makers get away with linking speed to off-road vehicles? This is false advertising.