Which manufacturers fit factory recovery points?

[XJ Junkie]

Yes please have a look. It’ll be interesting to know.

[grips]

Ok had a look yesterday. There is a 2 stamped on but I doubt it has anything to do with a rating. Maybe manufactures is too afraid to rate recovery points in case of failure and legal claims.

[ThysleRoux]

"Rating" is a term used by and a requirement for the hoisting of large items and has nothing to do with 4x4 recovery.

There is no way that any of us (OK, maybe Apoc excluded) can calculate the force that it will require to recover a stuck 4x4 accurately in the field - PERIOD. The looped factory "tow-hook" on the WJ passed inspection by Fred Bartens, the training and safety officer of the WCFWDC at the time, for snatch recoveries. As did the point on the tow bar - not the TOW BALL. I have much more faith in his experience than trust in some obscure Chinese "rating" standard......

[rudi.hinze]

thats a maximum load - not a rating for recovery or as a recovery point or even as a safe working load.

Hence my point. It’s Rated then, which is more than can be said for the vast major of what people are using.

The rating itself is s different discussion. But from what I’ve seen the aftermarket ones tend to be 5000t SWL, slightly stronger than the shackles.

you can get anything rated for a certain load with a simple test - you just lift a test weight and have it certified.

the problem is there is no such thing as a 'recovery rating' and a lot of people don't really understand the difference between 'SWL' and 'Breaking force' - something like a shackle with a 4,75ton SWL has a breaking force of 5 times that - 230kN

A 9000lb winch cable on the other hand will fail at very little more that 9000lbs = 40kN because thats it's breaking force not a safe working load (as you may not lift with that type of winch)

same goes for ropes - a 2ton SWL sling is good for 20tons (196kN) before it breaks, but a 13ton rope is only good for a little over 13 tons = 127kN because the 13 tons applies to it's breaking force.

so yes, you can have a hitch rated for a load - I think an M8 eyebolt is worth 500kg SWL , and if you fit it to your 4x4 you can claim it's a rated recovery hitch too - because it has a SWL rating, even if it's not suitable...

effectively the question is really, is your vehicle equipped with a recovery hitch with a breaking force of over (lets say) 100kN or 200kN or whatever someone has decided is a suitable limit for a recovery.

Well, ARB has gone about the matter differently by designing and producing for resale and fitment vehicle specific recovery point rated for use with a 4.75t rated bow shackle and 8000kg snatch strap. More so, ARB recovery points are rated in an angled direction of pull and this has been achieved for angles up to the maximum turn angle of the front wheels of the vehicle.

Probably why they are so expensive.



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[XJ Junkie]

Well, ARB has gone about the matter differently by designing and producing for resale and fitment vehicle specific recovery point rated for use with a 4.75t rated bow shackle and 8000kg snatch strap.

Yip. Same with Ironman & a few others. Yet car manufacturers don’t.

[Brandon]

Everything is a recovery point until it isn't.

Priced the ARB bolt on option. Not paying R4k.

Will have something made and fitted. Thus far I've survived with a mildly modified factory lashing point and the stupid bar on the back of my Ranger.

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[XJ Junkie]

R175 from Frontrunner, but unrated

[Woolf]

A question. Does the stamping not give rise to stress risers which then facilitate breaking?

[ThysleRoux]

A question. Does the stamping not give rise to stress risers which then facilitate breaking?

[Apocalypse]

Hence my point. It’s Rated then, which is more than can be said for the vast major of what people are using.

The rating itself is s different discussion. But from what I’ve seen the aftermarket ones tend to be 5000t SWL, slightly stronger than the shackles.

you can get anything rated for a certain load with a simple test - you just lift a test weight and have it certified.

the problem is there is no such thing as a 'recovery rating' and a lot of people don't really understand the difference between 'SWL' and 'Breaking force' - something like a shackle with a 4,75ton SWL has a breaking force of 5 times that - 230kN

A 9000lb winch cable on the other hand will fail at very little more that 9000lbs = 40kN because thats it's breaking force not a safe working load (as you may not lift with that type of winch)

same goes for ropes - a 2ton SWL sling is good for 20tons (196kN) before it breaks, but a 13ton rope is only good for a little over 13 tons = 127kN because the 13 tons applies to it's breaking force.

so yes, you can have a hitch rated for a load - I think an M8 eyebolt is worth 500kg SWL , and if you fit it to your 4x4 you can claim it's a rated recovery hitch too - because it has a SWL rating, even if it's not suitable...

effectively the question is really, is your vehicle equipped with a recovery hitch with a breaking force of over (lets say) 100kN or 200kN or whatever someone has decided is a suitable limit for a recovery.

Well, ARB has gone about the matter differently by designing and producing for resale and fitment vehicle specific recovery point rated for use with a 4.75t rated bow shackle and 8000kg snatch strap. More so, ARB recovery points are rated in an angled direction of pull and this has been achieved for angles up to the maximum turn angle of the front wheels of the vehicle.

Probably why they are so expensive.



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again, it's about a standard that doesn't exist.

the best ones can rally hope for in terms of a recovery point is a 'min breaking force' - e.g. guaranteed not to fail at less than 'x' Newtons

then some education into expected forces that can be applied would be required with some rules of thumb....


so, for example, it's pretty obvious that it's going to take a lot more force to extract a proper SUV thats 4 tons fully loaded and fitted with 37s that is sitting on it's chassis in thick gluttonous mud compared to a Fortuner that got stuck on a kerb at the mall.


it's not particularly hard to broadly estimate the basic forces - F=ma

you'll never know the (for want of a better word) stiction value of the bog you are in, but you can quickly work out the force if you have a few factors to hand

so lets say, a vehicle is bogged in and a Jimny comes scooting up, and the technical rope is broken out.

let us say that the rope is 20m long, has a breaking force of 100 kN (10 000kg) and will stretch by 0,5m at full load. i.e. if you exceed max load it will break.

Let us say the Jimny weighs 1500kg (with the boot packed to the hilt with a 6 pack of fruity alcopops)

and once it's all hitched, the Jimny hits 10m/s (36km/h) before the rope goes tight and it brings it to a halt in the 0,5m. the Vehicle in the mud remains unmoved...

so - very simply - 10m/s initial velocity , 0 final velocity, average velocity over 0,5m is 5m/s. stopping time is then 0,1s at 5m/s which is 50m/s/s decceleration (or 5G).

so, F=ma

1500 kg x 50m/s/s = 75000N = 75kN (what this ACTUALLY means is that , in this case, in reality , insufficient force has been applied to the rope to stretch it the full half metre which means the Jimny will stop in far less space, but will still not exceed the breaking force)


Then Frikkie arrives in his HiLux with a Lexus V8 engine and makes even less Impression than the Jimny.




Then we pull in the heavy guns. a 3ton something called Brutus with a 600hp motor and half a bottle of brandy behind the wheel.

in the 20m before the rope gets tight Brutus manages to hit 20m/s - 72km/h.

working with the maximum 0,5m stretch...

the bogged down vehicle remains unmoved. the Rope goes tight and the 3ton whatever starts stretching the rope. assuming it doesn't break he will stop in the 0,5m

so, initial velocity - 20m/s. final velocity 0. average over the half meter 10m/s . time taken to stop in 0,5m = 1/20thsec or 0,05seconds which means a deceleration of 200m/s/s - 20G. that should snap your head back, and possibly set off the airbags.

Force on recovery points - F=ma = 3000kg x 200m/s/s = 600 000N = 600kN - or significantly more than the technical rope (or link such as a shackle) can handle - and 8times the force the Jimny could apply, despite Brutus only hitting twice the speed.

the rope or shackle or recovery point breaks long before Brutus is jerked to a halt, and if a proper damping sheath isn't fitted, something very nasty will happen to one or other of the vehicles and/or drivers and/or pedestrians.



there is a big thing associated with this - traditionally, the stuck vehicle pulls out his recovery kit.

Technically, the 'stiction' in that mud pit could hold a Jimny back even in the face of a 500kN pull - but the force is applied by the recovering vehicle.

the weight of the stuck vehicle has NOTHING AT ALL to do with the force required to recover it or a 'recovery rating' .

so, the Jimny could have entirely suitable light weight recovery kit, but if he is the badly stuck one and hooks it up to Brutus, someone is going to eat some recovery gear.

and Brutus needs to be carrying FAR heavier gear than a Jimny.... and really - he should use his heavy recovery gear, not the Jimny's gear if the Jimny is stuck...

[Apocalypse]

I meant to add to the above... a very good point is raised about the direction of applied force to a recovery point or shackle. they are not all rated for anything more than a direct 90degree pull.... most are just strap down points.

[Apocalypse]

A question. Does the stamping not give rise to stress risers which then facilitate breaking?

the hook Neil posted is forged and the stamping will not harm it.

A cast item - like a bow shackle - will have the rating cast in as stamping it may well damage the structure...

[Reenen]

So you’ve met Allan with his Brutus?
But Allan doesn’t drink and 4x4...

https://youtu.be/MmzrO4D8jGE

[Apocalypse]

Et tu Brute’ !

[Oppies3800]

Who cares about recovery points if you never go offroad?

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