Recovery points

[Cowboy Dave]

Annoying though isn't it, because it leaves a nice healthy hole in the market that a savvy business could exploit. I'm not a betting man, but if I was, I reckon you could sell a hundred pairs of recovery points just on this forum if you came up with a design or two that would fit the bog stock and the most common bullbars. For ARB 100 probably isn't much in the scheme of things but you'd think someone could make it pay.

Presumably the potential liability for a business that got it wrong would be a strong deterrent to entering the market though.

[al coholic]

Pretty confident those hole centres are greater then 35mm so be needing to fabricate something not only to mount the hook, but possibly bring it forward and reduce possible scuffing from the bull bar

(Click for full size)


Something like this i think

Dave, the bolts highlighted in that pic are 50mm hole centres Might not suit the ones geek has bought obviously, bu surely someone must make a tow hook with 50mm hole centres.

Wishful thinking maybe

[al coholic]

I've said it before there is a mob here in Adelaide that are interested in having them made for us. They currently do them for the toyotas and nissans. Not rocket science, just a bent bit of thick steel and a few holes Just need to be sure it would fit the major brands of bull bars, ARB, TJM etc and get some numbers on commited buyers and they will look at doing them.

Just need someone to come up with dimensions that will fit the major bars or with no bar and go from there

Well, thats the first time ive heard you saying that Are you sure you mentioned it loudly enough?? Maybe use capitals

I would be interested for sure Tex.......I will do some measuring of different vehicles at Newnes on the weekend I would definitely want some like the pictures that have been posted recently though, so essentially a hook with a keeper.......I want to avoid using shackles

[RockoWallaby]

Would be interested too.
Untested, tho. Thats the risk of it, I guess.
But much better than nothing.

What would you do? Just for the one side? Keep the factory recovery point on the other?

[chick_magnet_0001]

you would get a lot higher rated point if it were closed (say 10mm plate with 25mm surrounding the hole)

[chick_magnet_0001]

you would think a mechanical engineer would be able to work something out like this cough cough coxy47...oooohhh your just a student

[snowman]

you would get a lot higher rated point if it were closed (say 10mm plate with 25mm surrounding the hole)

i think the advantage of the hook is the ease of use and lack of shackle projectile if the 'human element' does not put the shackle on properly.

[chick_magnet_0001]

you would get a lot higher rated point if it were closed (say 10mm plate with 25mm surrounding the hole)

The ones I'm talking about are 10mm or so plate bent to an 'L' with a largish hole/oval for a shackle NOT a hook.

ohh i somehow got the idea it was going to just be a bigger version of the hook we have now MY BAD

[chick_magnet_0001]

you would get a lot higher rated point if it were closed (say 10mm plate with 25mm surrounding the hole)

i think the advantage of the hook is the ease of use and lack of shackle projectile if the 'human element' does not put the shackle on properly.

agreed... probably why im not to fussed about this rated thing, im not stupid enough to drive into mud hole where i can't dig the car out first before attempting to recover it safely with limited pressure on the equipment....but for the rest of you crazies....***insert a host of QLD members**** [censored] you guys need this

[coxy47]

you would think a mechanical engineer would be able to work something out like this cough cough coxy47...oooohhh your just a student

Haha not any more just finished my last semester.

I'm generally inclined to go with the hook design as its one less thing to break. Tex is dead on with the reasoning. One less weak point is always better.

With an add on recovery point, the failure load at the mounting point on the chassis will nearly always be lower then the hook.

[Cowboy Dave]

hmm, I still reckon plate has to be stronger than those hooks that people have posted above. I know they're supposed to be rated and all but they just don't look as strong to me. I reckon my shackles are maybe twice as thick or more than the narrowest bits on those hooks.

[chick_magnet_0001]

you would think a mechanical engineer would be able to work something out like this cough cough coxy47...oooohhh your just a student

Haha not any more just finished my last semester.

I'm generally inclined to go with the hook design as its one less thing to break. Tex is dead on with the reasoning. One less weak point is always better.

With an add on recovery point, the failure load at the mounting point on the chassis will nearly always be lower then the hook.

congrats, got a job lined up?

[sm60089]

Not having looked under the front of mine yet, but would there be anything to stop you picking up on all four bolts in HC's pic?

The Chassis would probably be the weak point but a machined fitting properly heat treated could be fairly easily designed (with a few lug analysis calc's), especially if you could put a plate on the other side too.

[coxy47]

congrats, got a job lined up?

Thanks mate and yeah i have.

Not having looked under the front of mine yet, but would there be anything to stop you picking up on all four bolts in HC's pic?

The Chassis would probably be the weak point but a machined fitting properly heat treated could be fairly easily designed (with a few lug analysis calc's), especially if you could put a plate on the other side too.

As far as i know theres no reason that you couldnt pick up on all 4 bolts though i wouldnt think its particularly necessary. Its easy enough to get a couple of pre-fabbed recovery hooks on each side of the car and share the load with an equalizer strap across each side.

[tukadafoonday]

Does anyone know of rear recovery points if you don't have a tow bar for the recovery hitch?

[Cowboy Dave]

Mitsubishi sells a genuine tow hook. They come fitted to some of the lower spec models if there is no tow bar fitted. Search tow hook in here and you may even find some pictures.

[tukadafoonday]

Thanks cd

[NowForThe5th]

Mitsubishi genuine rear tow hook.



It's still sitting on my bench. Free to good home.

[Quinny]

Mate, I'll grab that with postage of course

[borngeek]

Mate, I'll grab that with postage of course

You going driving on sand again Mr plow?

[Quinny]

Mate, I'll grab that with postage of course

You going driving on sand again Mr plow?

errrr... maybe

At the moment I've got no recovery points at the back ... Until I get my rear bar, anyways

[Cowboy Dave]

Come to think of it I have one of those somewhere too. Now if only I could recall where

[4wd26]

Stolen from another forum- but I have seen these bend, and this is the science to prove it.

I can't make the picture display smaller and the right side with the scale has been cropped off it. If you right click and hit "view image" then it'll show the whole picture in a new window. You'll be able to see the stress scale etc.
Peak stress is roughly 1000MPa, mild steel starts to bend around 250MPa.

Basically that hook would have to be made from extremely high strength steel to not bend at the 4500kg stamped on the side of it.
Being that they're cast, my guess is pig iron and I wouldn't trust them at the rating they're sold at.

After doing that, I'll be putting in my own design recovery eyes and only using hooks for mild recovery.

Some more info- would love to find the actual article rather than the quote, but gives some idea- NOT ALL HOOKS are the same.

I have carried out several hook tests on a test rig.
The bighorn hook with 10mm bolts snaps the bolts around 5 tonne
Drilled out to 12 mm, 8.8 bolts still fail but 10.9s hold till the hook breaks @ 8.18 tonnes.
The Black Rat Black hook snapped around 5 Tonne
The Black Rat Chrome hook straightened around 5 Tonne
The Supa Cheap Ridge Rider Black hook snapped around 8 Tonne
The Bush Ranger Black hook straightened around 5 Tonne
3/4 shank towball snapped around 8 Tonne
Pintle Hook/Nato Coupling stripped the 10mm mounting bolts ie Patrol, around 12 Tonne
Pintle Hook with 12mm 8.8 bolts stalled the test rig around 20 Tonne
The Snatchmaster hooks from Cookes straighten around 9.8 Tonne, this opens a new can of worms as the M12x1.75 bolts broke first.

Standard Toyota L/C hooks straighten @ 4.6 tonnes,
Hilux hooks however, by design, push the rope further away from the mounting plane of the bolts, causing the rear bolt to stretch and snap , then shearing the front bolt, 8.8 bolts failing @ 4.5 tonnes.

The Cookes hooks consistently have the highest rating straightening at arround 8 to 9 Tonnes but the bolts they supply are sometimes only 4.6 instead of 8.8 and both of these can let go before the hook straightens.
A Cookes hook with 1/2" grade 8 bolts is my answer.

[fraz91]

It's interesting that the SCA option broke at 8T, actually outlasting some of the gear that would be considered "higher quality". That being said, it snapped, which would mean there was a projectile. Much more dangerous when you consider a bent one would need to be replaced anyway.

[4wd26]

note also that the testing would have been static- in a test bed and force applied slowly.

Think to any snatch recovery and the forces are instant (and usually underestimated).

SO IT IS IMPORTANT THAT THE SNATCH STRAP IS THE WEAKEST LINK


one of the reasons "rated points disappeared" was the purchase of 16,000kg straps (stronger than the chassis) because the lighter straps were breaking - that should be telling you something- not that you need to get a thicker strap. (sorry for harping- back in my box)