Safety: Towing a Side-Stuck

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Safety: Towing a Side-Stuck

Post by PR »

Towing a Sidestuck

by PR, for AD4x4

This article follows on from an introductory article on how to tow a stuck vehicle: please read Towing Stucks first - http://www.ad4x4.com/club/viewtopic.php?f=1&t=7125



On level ground there's not much that can go wrong, but on the steep inclines of sand dunes the situation is different and some attention must be paid to simple laws of physics and vehicle weight displacement.

On the kind of angles that steep dunes offer, a 4x4 vehicle is safe when going straight up or down, that is, when the vehicle is perpendicular to the dune. You can climb as far up the steepest dune as you like, and reverse down in a straight line. And in 1st gear and low range you can descend a dune in safety when you drive straight down.

Image

The problem is when the vehicle is sideways on an angle; that is, when it is off-camber, or parallel to the dune line. The vehicle is much less stable when the weight is on one side, and, to make things worse, sand on the lower side will give way, worsening the angle and blocking the wheels on the downhill side. The vehicle may tip over. It's usually a very slow roll and passengers with safety belts on are rarely injured - nothing compared to a roll off the highway. However, I'm sure you will agree it's best prevented.

Image

So, driving straight up or down a dune is fine, but turning sideways or traversing a dune sideways is not.

You might see experienced drivers running up a dune and turning around and then screaming back down, leaving nice rainbow-shaped tracks. They can do so because they know the amount of momentum they must maintain to prevent a roll. And even then, they are consciously taking a considerable risk. If they misjudge, or if they hit a soft spot, or if there's a hidden hard ridge, and they're caught in the wrong spot, they might roll over, too.

If you are caught stuck sideways, do not panic and do not open the doors. Do not allow any person to walk or stand downhill from your car.

CLEAR THE DOWNHILL - DON'T STAND THERE!
Image

Direct two trusty and hefty friends to add weight to the uphill side; they must of course jump off if the car starts rolling, but in the meantime, adding their weight will make a big difference in preventing a roll.

Image

Digging sand away from the downhill wheels may seem a good option, but it just puts a person at risk, might worsen the angle, and sand will just run down and fill the sand that is removed - so don't do it.

Image

There are a few possibilities for recovery, depending on the situation, but here on the internet I'll first mention the main, simple procedure.

1. Anchor car on uphill side
2. Clear any people/cars from downhill side
3. Attach tow strap to rear downhill corner (never uphill side, middle is iffy)
4. Very gently, and I mean very gently, pull stuck car so that the rear end moves downhill just 20cm - stop!
5. Stuck driver tries to reverse
6. If not free, repeat pull for another 20cm
7. When stuck driver can reverse down slowly, release the uphill anchors.

Attaching the tow strap to the front is more risky, since that's where the engine's weight is.

Whatever you do, do not pull hard!

Image

Now, some possibilities:

When you are still moving, and you sense you are about to get stuck, immediately gun it and turn downhill. If you are not stuck parallel to the dune, this makes recovery much simpler.

When you come to a stop parallel on a sideslope, do not spin your wheels. It digs the downhill wheels in and worsens the rollover angle.

If you have a rear-wheel-drive car, there's a nice and easy technique to get out of a sidestuck. When you realize you are stuck, disengage 4x4, and reverse spinning the wheels. Since only the rear wheels turn, the sand will shift, and the rear will swing downhill. Then engage 4x4 and reverse down slowly.

If you have difflock, engage and try. The problem with self-recovery from a sidestuck is that all the weight is on the downhill wheels, so without difflocks the uphill wheels will spin uselessly while the downhill wheels won't get any power. Engaging difflock will force the downhill wheels to also turn, enhancing your chances of self-recovery.

So there you have it. Stuck on a sideslope deserves serious consideration for everyone's safety, and to avoid damage to your car.

PLEASE STAY SAFE - a moment of foolishness can become a lifetime of regret
Image
Last edited by PR on Thu Jun 25, 2009 5:41 pm, edited 1 time in total.

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Re: Safety: Towing a Side-Stuck

Post by TINTIN »

This is a very sticky situation. My first stuck was a side sloping one and I was a little nervous to say the least. It turns out I wasn't on much of an angle, but it was my very first time in the sand and only 10 minutes into the trip so it kinda scared me a little. Very informative again though PR. Thanks buddy. :ad4x4:
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Re: Safety: Towing a Side-Stuck

Post by Xtreme »

Thanks again Pr for this useful post.
I have some side stucks too, but never needed recovery from another car ... Always worked with low range diff lock.
But I agree with you that it can be really dangerous specially without enough experience to handle the situation.
First time it happened to me, I was scared and had the feeling I'm going to roll over, but when you know your car better, you know your limits.
Thanks
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Re: Safety: Towing a Side-Stuck

Post by PR »

It's my pleasure to share, guys 8)

To add a little theory, the angle at which sand dunes exist is around 32 degrees, according to Encyclopedia Britannica.

This is called the angle of repose, and basically over that angle sand will flow down by itself. So any dune with a slipface can be assumed to be around 32 degrees (this can change if the sand is wet, if the grains are coarse or fine, etc. - also the downhill wheels will dig in, worsening the angle, so this is not exact)

Image
(http://en.wikipedia.org/wiki/File:Angleofrepose.png)

But, if for discussion sake we assume 32 degrees on a sideslope, let's compare it to your car roll-over angle. That is the angle at which your car will roll-over sideways as declared by the manufacturer. Again this is not exact, as data is from Internet, sagging suspension, how much weight is in the car, and where it is stowed (roof is the worse), tyre pressure, etc., etc.

MITSUBISHI PAJERO BK 3.8L V6 GLS SWB AT: 45 degrees roll-over angle
TOYOTA LAND CRUISER PRADO 4.0 VX AT: 42
TOYOTA LAND CRUISER 100 4.7 V8 VX AT: 45
RANGE ROVER SPORT 4.4 V8 HSE COMMANDSHIFT MY08: 47
LAND ROVER DEFENDER 110 2.4TD SW: 35 --------WOW!!! Not good!
LAND ROVER DISCOVERY 4.0 V8 HSE AT: 30 ----- shoo?
KIA SPORTAGE 2.7 4X4 AT: 18 ----- is this right??? LOL this is going to flip over in Spinney's parking lot!
NISSAN PATROL 4.8 GRX TIPTRONIC: 48
NISSAN PATHFINDER 4.0 V6 LE TIPTRONIC: 48.7
HUMMER H3 V8 ADVENTURE HYDRA-MATIC: 36 ---- oh oh! thought Hummer would do better
JEEP GRAND CHEROKEE 4.7L LAREDO AT: 37.7---- cutting it pretty close
JEEP WRANGLER 4.0L SAHARA AT: 46
HYUNDAI TUCSON 2.7 V6 GLS 4X4 H-MATIC: 36

Data from http://www.um.co.za/specifications/

Find out the roll-over angle for your model.

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Re: Safety: Towing a Side-Stuck

Post by Bulldozer »

Good Informative stuff man u say it all
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Re: Safety: Towing a Side-Stuck

Post by Andy »

PR wrote:It's my pleasure to share, guys 8)

To add a little theory, the angle at which sand dunes exist is around 32 degrees, according to Encyclopedia Britannica.

This is called the angle of repose, and basically over that angle sand will flow down by itself. So any dune with a slipface can be assumed to be around 32 degrees (this can change if the sand is wet, if the grains are coarse or fine, etc. - also the downhill wheels will dig in, worsening the angle, so this is not exact)

Image
(http://en.wikipedia.org/wiki/File:Angleofrepose.png)

But, if for discussion sake we assume 32 degrees on a sideslope, let's compare it to your car roll-over angle. That is the angle at which your car will roll-over sideways as declared by the manufacturer. Again this is not exact, as data is from Internet, sagging suspension, how much weight is in the car, and where it is stowed (roof is the worse), tyre pressure, etc., etc.

MITSUBISHI PAJERO BK 3.8L V6 GLS SWB AT: 45 degrees roll-over angle
TOYOTA LAND CRUISER PRADO 4.0 VX AT: 42
TOYOTA LAND CRUISER 100 4.7 V8 VX AT: 45
RANGE ROVER SPORT 4.4 V8 HSE COMMANDSHIFT MY08: 47
LAND ROVER DEFENDER 110 2.4TD SW: 35 --------WOW!!! Not good!
LAND ROVER DISCOVERY 4.0 V8 HSE AT: 30 ----- shoo?
KIA SPORTAGE 2.7 4X4 AT: 18 ----- is this right??? LOL this is going to flip over in Spinney's parking lot!
NISSAN PATROL 4.8 GRX TIPTRONIC: 48
NISSAN PATHFINDER 4.0 V6 LE TIPTRONIC: 48.7
HUMMER H3 V8 ADVENTURE HYDRA-MATIC: 36 ---- oh oh! thought Hummer would do better
JEEP GRAND CHEROKEE 4.7L LAREDO AT: 37.7---- cutting it pretty close
JEEP WRANGLER 4.0L SAHARA AT: 46
HYUNDAI TUCSON 2.7 V6 GLS 4X4 H-MATIC: 36

Data from http://www.um.co.za/specifications/

Find out the roll-over angle for your model.








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Re: Safety: Towing a Side-Stuck

Post by PR »

LOL - that's almost 50 degrees, pretty good! Almost as hot as outside. :wink:

Personally, I was surprised by the Land Rovers... can someone confirm if the figures are correct? Especially for the Discovery at 30 degrees; if that's true you really need to keep it off the slopes.

I wasn't expecting that. Kia, Hyundai, OK, they're not really designed for tough off-roading, but Land Rovers? And then the Rangie back up to a healthy 47...

Strange. Though it's true they look a little narrow and high.

Maybe that's with the stock skinny UK tyres...

To calculate the actual roll-over angle for your own car is incredibly complex, so we can't really get more precise. I guess an inclinometer would tell us... who has one installed and can park on a good sideslope? :lol:
Last edited by PR on Thu Jun 25, 2009 7:18 pm, edited 1 time in total.

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Re: Safety: Towing a Side-Stuck

Post by Xtreme »

PR wrote: MITSUBISHI PAJERO BK 3.8L V6 GLS SWB AT 2008 and above: 45 degrees roll-over angle
MITSUBISHI PAJERO BK 3.8L V6 GLS SWB AT below 2008 SWB and LWB 48 degrees
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Re: Safety: Towing a Side-Stuck

Post by mike0967 »

Andy wrote:Yes Yes Yes "The Plastic Pig" finally won something .... :mrgreen:
Those figures relate to bog stock cars, non of our cars is stock mate, you got lift kit and bigger tyres as well :roll: :wink:
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Re: Safety: Towing a Side-Stuck

Post by Bulldozer »

PR wrote:LOL - that's almost 50 degrees, pretty good! Almost as hot as outside. :wink:

Personally, I was surprised by the Land Rovers... can someone confirm if the figures are correct? Especially for the Discovery at 30 degrees; if that's true you really need to keep it off the slopes.

I wasn't expecting that. Kia, Hyundai, OK, they're not really designed for tough off-roading, but Land Rovers? And then the Rangie back up to a healthy 47...

Strange. Though it's true they look a little narrow and high.

Maybe that's with the stock skinny UK tyres...

To calculate the actual roll-over angle for your own car is incredibly complex, so we can't really get more precise. I guess an inclinometer would tell us... who has one installed and can park on a good sideslope? :lol:
Thats why u need to keep them on the straight gravel roads, Gents the figures for stock cars, lift kit, bigger tyres, wheel spacers for sure will make a difference
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Re: Safety: Towing a Side-Stuck

Post by Jo »

Andy wrote:Yes Yes Yes "The Plastic Pig" finally won something .... :mrgreen:
Andy, what does it help you? You will not be able to reach to a dune slope wher you are even close to this angle... you PP will be desintegrate before... :twisted:

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Re: Safety: Towing a Side-Stuck

Post by PR »

iPhone app for car inclinometer, $0.99!

http://appshopper.com/utilities/car-clinometer

Image

8)

'xcept I don't have an iPhone! LOL

Maybe I can use a protactor and weight on a string... LOOOOOOL

Image

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Re: Safety: Towing a Side-Stuck

Post by Andy »

mike0967 wrote:
Andy wrote:Yes Yes Yes "The Plastic Pig" finally won something .... :mrgreen:
Those figures relate to bog stock cars, non of our cars is stock mate, you got lift kit and bigger tyres as well :roll: :wink:
Jo wrote:
Andy wrote:Yes Yes Yes "The Plastic Pig" finally won something .... :mrgreen:
Andy, what does it help you? You will not be able to reach to a dune slope wher you are even close to this angle... you PP will be desintegrate before... :twisted:

:hat:
Guys why did you have spoil my moment of glory.... :crying: :suicide:

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Re: Safety: Towing a Side-Stuck

Post by nuclear »

Andy wrote:
PR wrote:It's my pleasure to share, guys 8)

To add a little theory, the angle at which sand dunes exist is around 32 degrees, according to Encyclopedia Britannica.

This is called the angle of repose, and basically over that angle sand will flow down by itself. So any dune with a slipface can be assumed to be around 32 degrees (this can change if the sand is wet, if the grains are coarse or fine, etc. - also the downhill wheels will dig in, worsening the angle, so this is not exact)

Image
(http://en.wikipedia.org/wiki/File:Angleofrepose.png)

But, if for discussion sake we assume 32 degrees on a sideslope, let's compare it to your car roll-over angle. That is the angle at which your car will roll-over sideways as declared by the manufacturer. Again this is not exact, as data is from Internet, sagging suspension, how much weight is in the car, and where it is stowed (roof is the worse), tyre pressure, etc., etc.

MITSUBISHI PAJERO BK 3.8L V6 GLS SWB AT: 45 degrees roll-over angle
TOYOTA LAND CRUISER PRADO 4.0 VX AT: 42
TOYOTA LAND CRUISER 100 4.7 V8 VX AT: 45
RANGE ROVER SPORT 4.4 V8 HSE COMMANDSHIFT MY08: 47
LAND ROVER DEFENDER 110 2.4TD SW: 35 --------WOW!!! Not good!
LAND ROVER DISCOVERY 4.0 V8 HSE AT: 30 ----- shoo?
KIA SPORTAGE 2.7 4X4 AT: 18 ----- is this right??? LOL this is going to flip over in Spinney's parking lot!
NISSAN PATROL 4.8 GRX TIPTRONIC: 48
NISSAN PATHFINDER 4.0 V6 LE TIPTRONIC: 48.7
HUMMER H3 V8 ADVENTURE HYDRA-MATIC: 36 ---- oh oh! thought Hummer would do better
JEEP GRAND CHEROKEE 4.7L LAREDO AT: 37.7---- cutting it pretty close
JEEP WRANGLER 4.0L SAHARA AT: 46
HYUNDAI TUCSON 2.7 V6 GLS 4X4 H-MATIC: 36

Data from http://www.um.co.za/specifications/

Find out the roll-over angle for your model.









Yes Yes Yes "The Plastic Pig" finally won something .... :mrgreen:


Don't be so sure Andy .. for less than this angle .. my side Air Bag opened sudenly :(
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Re: Safety: Towing a Side-Stuck

Post by nuclear »

Bulldozer wrote:
PR wrote:LOL - that's almost 50 degrees, pretty good! Almost as hot as outside. :wink:

Personally, I was surprised by the Land Rovers... can someone confirm if the figures are correct? Especially for the Discovery at 30 degrees; if that's true you really need to keep it off the slopes.

I wasn't expecting that. Kia, Hyundai, OK, they're not really designed for tough off-roading, but Land Rovers? And then the Rangie back up to a healthy 47...

Strange. Though it's true they look a little narrow and high.

Maybe that's with the stock skinny UK tyres...

To calculate the actual roll-over angle for your own car is incredibly complex, so we can't really get more precise. I guess an inclinometer would tell us... who has one installed and can park on a good sideslope? :lol:
Thats why u need to keep them on the straight gravel roads, Gents the figures for stock cars, lift kit, bigger tyres, wheel spacers for sure will make a difference
Very good point Bulldoozer .. Beside, the type of sand (loose sand or denes sand) is also a factor .. the more loose sand the less stapility angle you get ..

I liked what Andy and his friend did with the landrover Defender - see above pic.- By this way .. they are moving the CG (Centre of Gravity) of the car up (to give a resistance turning over moment) beside they are increasing the moment of inertia in the roll over direction
ANTI JEEP
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The Journey of 1000 miles begins with a broken fan belt & a leaky tire ;)

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