Reversing down a cliff - what happens if one wheel goes of?
Discussion
Was discussing this the other day
Presume your reversing a 4x4 down an icy slippery hill and you end up close the cliff edge with one of your rear tyres hanging off.
At this point can you simply driver back up the hill using the 3 tyres that have traction or would it send the car sideways (I.e risk the other rear wheel going off also)
Presume your reversing a 4x4 down an icy slippery hill and you end up close the cliff edge with one of your rear tyres hanging off.
At this point can you simply driver back up the hill using the 3 tyres that have traction or would it send the car sideways (I.e risk the other rear wheel going off also)
I'm pretty sure if it was me I'd fall off the cliff but ...
4x4 in centre diff lock means the front wheels will have traction. The rear wheels without a locking diff the wheel in the air will spin the one on the ground won't move. I have watched people do this in competition and they would give it some beans too.
Therefore you simply drive away normally.
This is based on good old Land Rover technology none of this fancy clicky clacky traction control. I assume if you have the clicky clacky it will just drive straight off. That is surely what it's supposed to do.
Now I await to be corrected
Mike
4x4 in centre diff lock means the front wheels will have traction. The rear wheels without a locking diff the wheel in the air will spin the one on the ground won't move. I have watched people do this in competition and they would give it some beans too.
Therefore you simply drive away normally.
This is based on good old Land Rover technology none of this fancy clicky clacky traction control. I assume if you have the clicky clacky it will just drive straight off. That is surely what it's supposed to do.
Now I await to be corrected
Mike
need a more detailed scenario really...
what sort of 4 x 4 setup; proper live axle with lockers type machine / soft roader / 4wd performance car?
whats the weight distribution?
does it have low range gearing?
what tyres is it using?
at what angle is the ground immediately before the vertical drop?
what are the ground conditions/what is the ground made of?
does icy mean frost on the ground or sheet ice?
is the car sitting on the body / chassis / sill or is it nose heavy enough that the weight is taken on the other 3 wheels?
how far below the body does the unweighted wheel hang?
etc etc
however without knowing all details and in the spirit of the topic I would broadly guesstimate that a proper 4 x 4 would manage to drag itself back up, a soft roader or performance 4wd car would not
what sort of 4 x 4 setup; proper live axle with lockers type machine / soft roader / 4wd performance car?
whats the weight distribution?
does it have low range gearing?
what tyres is it using?
at what angle is the ground immediately before the vertical drop?
what are the ground conditions/what is the ground made of?
does icy mean frost on the ground or sheet ice?
is the car sitting on the body / chassis / sill or is it nose heavy enough that the weight is taken on the other 3 wheels?
how far below the body does the unweighted wheel hang?
etc etc
however without knowing all details and in the spirit of the topic I would broadly guesstimate that a proper 4 x 4 would manage to drag itself back up, a soft roader or performance 4wd car would not
If you've slid on ice then there is a risk that any attempt to drive away could see further sliding.
In your scenario let's assume you just have one wheel in the air, the other 3 are in full contact with the ground & the vehicle isn't grounded.
As far as where the drive would go with one wheel in the air it depends what the vehicle is fitted with.
In the absence of a lockable centre differential - whether that be manually locked, a viscous coupling or some other sort of mechanism - the power will take the line of least resistance & you'll just spin the wheel in the air.
With a locking centre differential once the locking comes into play then power will be directed to both the front & rear differentials. The front wheels will be turned & drive the vehicle but the rear differential will allow the power to go to the wheel in the air & the other wheel won't do anything.
If you have a lockable centre differential AND a locking mechanism on the axle differentials then power would go equally to all wheels
Traction control and Electronic Stability Control now perform the role of locking diffs by applying the brakes to a spinning wheel.
In your scenario let's assume you just have one wheel in the air, the other 3 are in full contact with the ground & the vehicle isn't grounded.
As far as where the drive would go with one wheel in the air it depends what the vehicle is fitted with.
In the absence of a lockable centre differential - whether that be manually locked, a viscous coupling or some other sort of mechanism - the power will take the line of least resistance & you'll just spin the wheel in the air.
With a locking centre differential once the locking comes into play then power will be directed to both the front & rear differentials. The front wheels will be turned & drive the vehicle but the rear differential will allow the power to go to the wheel in the air & the other wheel won't do anything.
If you have a lockable centre differential AND a locking mechanism on the axle differentials then power would go equally to all wheels
Traction control and Electronic Stability Control now perform the role of locking diffs by applying the brakes to a spinning wheel.
Edited by paintman on Wednesday 8th May 08:39
Thanks for your answers - awesome.
In the scenario it was a new cayenne reversing down a snowed over hill (presume some invisible sheet ice)
The driver was worried he would get too close the cliff in a slide and end up with a tyre off.
My point was as long as majority of the wheels can get traction and weight distribution is ok - the car should be able to pull it self up without any issues - adding ice in mix could changes things
In the scenario it was a new cayenne reversing down a snowed over hill (presume some invisible sheet ice)
The driver was worried he would get too close the cliff in a slide and end up with a tyre off.
My point was as long as majority of the wheels can get traction and weight distribution is ok - the car should be able to pull it self up without any issues - adding ice in mix could changes things
Edited by stef1808 on Wednesday 8th May 14:55
stef1808 said:
Thanks for your answers - awesome.
In the scenario it was a new cayenne reversing down a snowed over hill (presume some invisible sheet ice)
The driver was worried he would get too close the cliff in a slide and end up with a tyre off.
My point was as long as majority of the wheels can get traction and weight distribution is ok - the car should be able to pull it self up without any issues - adding ice in mix could changes things
Too many variables.In the scenario it was a new cayenne reversing down a snowed over hill (presume some invisible sheet ice)
The driver was worried he would get too close the cliff in a slide and end up with a tyre off.
My point was as long as majority of the wheels can get traction and weight distribution is ok - the car should be able to pull it self up without any issues - adding ice in mix could changes things
Edited by stef1808 on Wednesday 8th May 14:55
What size cliff, which wheel, surface type. If the driver is worried about being able to reverse, chances are they are not a capable off road driver and unlikely to be able to use the vehicle to it's fullest extent.
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