At what angle will a 4wd roll?

Submitted: Friday, Jul 29, 2005 at 20:20
ThreadID: 25168 Views:11575 Replies:12 FollowUps:6
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On our day trip to Gembrook last Saturday Cary posed the question.

He nearly rolled his Navara and said it was showing 40 degrees on the inclinometer.

Any feedback on how far you have tilted your car and what the reading was on the inclinometer would be appreciated. I'm still a novice and often feel that the car is leaning too far without having any idea of how much trouble I'm in. I'd like to fit an inclinometer, just as long as I understand what the readings mean. It would give me some sense of comfort.

Cheers,

Jim.
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Reply By: Member - Duncan W (WA) - Friday, Jul 29, 2005 at 20:38

Friday, Jul 29, 2005 at 20:38
Jim, it's different for different vehicles. I think it's mentioned in the vehicle's handbook? Nope just checked. I would suspect that the type of suspension and the COG of the car would all contribute.

Not much help sorry.

Dunc.
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Follow Up By: Exploder - Friday, Jul 29, 2005 at 21:02

Friday, Jul 29, 2005 at 21:02
It all depends on suspension how you are driving it and COG.

Have only come close once in a Discovery, I was not driving and was not my car, it’s a long story, but the 2 second or so the 4WD was balancing on the 2 passenger side tyre’s before dropping back onto the other 2 felt like about 15 and me and the other bloke had that holly Shi* expression stamped on owe faces.
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Reply By: Footloose - Friday, Jul 29, 2005 at 20:47

Friday, Jul 29, 2005 at 20:47
Inclinometers aren't worth a pinch of ^%^&*(% IMHO. By the time you've looked at it and said "Oh my goodness" or words to that effect, you've gone. They might work well on gently sloping grades, but in the real 4wd world ?

So many other factors come into the equation. I met a guy 2 weeks ago who had rolled his Troopy in truck wheel tracks on the Tanami doing 40k/h. No inclinometer needed.

Lifts, heavy loads on roofracks, violent manouvers and many other things can all be factors in rollovers.

I rekkon that every new 4wd should have a sticker attached by law.

"Drive me like a sports car and I fall over".

Sorry, didn't really answer the question did I ?
All I can suggest is that you join a 4wd club and gain controlled experience.
To be honest not only don't I know if my vehicle is about to roll over, I never want to know :))
AnswerID: 122778

Follow Up By: MikeyS - Friday, Jul 29, 2005 at 22:01

Friday, Jul 29, 2005 at 22:01
Jimbo, I reckon Footloose has got it well covered. About the only use for an inclinometer is when you have stopped on what you think is a steepish incline, (so the thing has stopped jiggling around) and you can say " Oh, that's only a 25 degree incline with a 15 degree slide slope". It's generally never actually as steep as it feels. If you're really getting close to a roll-over, the last thing you are likely to be doing, or even want to be doing, is looking at the thing. Because the next thing you'll see it doing is acting like the artificial horizon in a stunt plane doing a barrel roll.

And as has been alluded to, the relevant factor is the centre of gravity, and the forces acting on the vehicle so the critical angle would change between different vehicle, how a vehicle is loaded, how fast it is turning, the nature of the ground beneath the tyres etc. Don't people roll Explorers in the States just going round highway corners? Highish centre of gravity + slight off-cambered road shoulder + excessive speed = rollover. Put a Ferrari stationary on a 70 degree side-slope and it probably still wouldn't tip. Low profile tyres, stiff suspension, very low centre of gravity, especially with 120kg driver with butt scraping the ground, no sideways forces= no rollover.

Too many variables to make the angles mean anything. There are much more useful toys to buy.

Stay upright
MikeyS
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Follow Up By: BenSpoon - Monday, Aug 01, 2005 at 22:07

Monday, Aug 01, 2005 at 22:07
I reckon they are some value, but lacking in the way most people use them- mainly because they dont take into account the momentum of your 3 tonne bus. I have seen them off the 40-degree scale (so I cant say their actual value, but more than 40), and I have been in a 4by rolled on flat ground, but hit an embankment side on at 80km/h.

They are valuable only if you have no concept of balance. Maybe if you had no ears you'd have a use for it. I have been in cars I could literally reach out the passenger window and just touch the ground (SWB patrol and sierra) but try the same in different vehicle and you'll roll.

Just keep building your experience in yours, and if you dont write it off you'll learn its limits. Failing that, ply a bloke with the same car with caffeine and sugar and egg him on.
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FollowupID: 378312

Reply By: See You - Friday, Jul 29, 2005 at 20:51

Friday, Jul 29, 2005 at 20:51
It would depend on how high up Truckster was sitting. LOLOLOLOL
AnswerID: 122779

Reply By: Willem - Friday, Jul 29, 2005 at 21:20

Friday, Jul 29, 2005 at 21:20
I would hazard a guess that at a 45.1 degree angle you are beyond the point of no return.

I have only been over twice in a 4by and three times in a car. The times in the 4by were due to the earth moving for me . lol Both times the river embankment gave way.

The cars were just youthfull recklessness
AnswerID: 122787

Follow Up By: Member - Smocky (NSW) - Monday, Aug 01, 2005 at 10:57

Monday, Aug 01, 2005 at 10:57
It's about getting the centre of gravity outside your wheel track. On some cars, that might be 36 degrees.

Smocky.
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FollowupID: 378205

Reply By: westBob - Friday, Jul 29, 2005 at 22:05

Friday, Jul 29, 2005 at 22:05
an old bloke once told me if you are worried your 4x4 is about to roll hop out try to push it over if it rolls over you were better off not being in there in the first place ... some thing that has always stuck in my head . cheers Bob
AnswerID: 122798

Reply By: Member - Davoe (Widgiemooltha) - Friday, Jul 29, 2005 at 22:50

Friday, Jul 29, 2005 at 22:50
stand behind your 4by and mentally draw diagonal lines accross the back ie top left hand of vehicle to bottom right hand tyre (outer edge of tyre) Where both lines intersect is the centre point of your 4by
Now put your hand or a ruler so it goes past the outer edge of the tyre anf through this imaginary middle point, As your 4by gets on an angle your hand or ruler becomes more upright. When it is 90 deg you are starting to run the risk of going over. This is a general rule and doest take into account overloaded roof racks. Generally your bum will start to pucker up well before you are even getting close to going over
AnswerID: 122810

Reply By: i3websolution - Friday, Jul 29, 2005 at 23:16

Friday, Jul 29, 2005 at 23:16
Nissan Patrol GU is about 60 degree.
It is from the Jap spec.
AnswerID: 122815

Follow Up By: Michael ( Moss Vale NSW) - Sunday, Jul 31, 2005 at 18:55

Sunday, Jul 31, 2005 at 18:55
Go the Patrols!!!
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Reply By: Bob of KAOS - Friday, Jul 29, 2005 at 23:34

Friday, Jul 29, 2005 at 23:34
This is where the sunroof comes into its own. If you open the sunroof and there is dirt its a safe bet you have rolled (they are phasing out dirt rooves in shopping centre carparks making this explanation less likely) If some doubt remains you can confirm this on your inclinometer - the black hemisphere is on top. All 4WDs should therefore be fitted with inclinometers.
AnswerID: 122820

Follow Up By: Skinny- Monday, Aug 01, 2005 at 11:18

Monday, Aug 01, 2005 at 11:18
Good one Bob, I use a similar method. I drive with my elbow out the window. When I feel the ground hit my elbow I know I am going over.

They tell me with the new laws though I will get a bigger fine and lose more points putting my elbow out the window than sitting on the roof while going down the highway.

Perhaps I could mount a new driving position, even easier to tell when i am about to roll over from the bonnet.

Skinny
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FollowupID: 378206

Reply By: Member Eric - Saturday, Jul 30, 2005 at 08:01

Saturday, Jul 30, 2005 at 08:01
I agree with the agove coments , so your drivinh alont , you slip off a track and your meter showes that yo uhave slipped to far and you will roll over . Ok , I want you to slop sliding now . Ok ill say it again , stop sliding now . Gee it dodnt stop , im on my roof lol.

Those guages were auwson gadgets for Tootrak tractor owners to show off to there friends when they go up a steep driveway lol.
AnswerID: 122830

Reply By: Member - JohnR (Vic)&Moses - Saturday, Jul 30, 2005 at 10:15

Saturday, Jul 30, 2005 at 10:15
Jim, I don't have any idea either but having seen a couple of photos of the episode , in both cases the vehicle would only be capable of sideways in the wrong direction unless it was steered directly down hill if that was possible. Not with the trees right there obviously.

I reckon there were decisions you must have made before the point where the photos were taken that would have stopped you going that far. I guess that is obvious as you didn't get into the same pickle. This guy did twice!

I can remeber when a young guy I was driving tractors without roll cages, being in similar situations though. Manouever to drive directly downhill
Cheers,
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AnswerID: 122846

Reply By: Diamond (Vic) - Saturday, Jul 30, 2005 at 18:42

Saturday, Jul 30, 2005 at 18:42
cant help you with an answer but a while back in a mates hilux driving along the side of a hill i remember instead of looking over my shoulder to talk to him i had to look up way way up lol
AnswerID: 122911

Reply By: Member - Smocky (NSW) - Monday, Aug 01, 2005 at 11:09

Monday, Aug 01, 2005 at 11:09
Hi Jimbo,

There's quite a bit to this and there's no way I'm going to explain it all. But a couple of things,

IF MOVING, then forces come into play and can roll you much more easily. For example, doing 100Km/hr and yanking the steering wheel full loock right will probably roll most cars.

IF STATIONARY, then it's about keeping your CENTRE OF GRAVITY between your wheels. The COG is NOT the centre of your car. Lot's of other things will lift you COG, like roofracks, load on the roof, passengers, spare tyre on the back etc. It's probably somewhere around the top of your bonnet and slightly passenger side of the dash and will differ depending how many passengers.

ALSO, once you are on a lean, anything that changes can have an effect, like opening the bottom door. This will move your COG further across to the downward side and if this moves the COG outside your wheel, over she will go. We had a really good demo at the 4WD course I did.

I don't believe the Nissan Patrols will get anywhere near 60 degrees with at least a driver in the car. I was on a slope of around 30 degrees on the training course and I can tell you I didn't want to be there. The car was pretty stable, but it wouldn't have taken too many more degrees to get loose. Maybe 40 degrees would see most 4WD's in trouble.

Cheers,

Smocky.
AnswerID: 123113

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