REAR RECOVERY HOOK

[geeves]

Bolts bend even when fully torqued because they will stretch under load. I havent seen a hook come off but have seen photos which dont always tell the whole story. A few years ago nz4wd mag did a test on snatch straps where they used a hydrolic jig designed for testing chains etc. The hook was bolted to a piece of 5x25mm steel with a strong chain attached to the other end and the strap attached to the hook and the other end to the jig. In the first test the bolts snapped releasing the hook at about 7 ton. These were 8.8 bolts but no info was given as to how they were tightened. Also the metal bar had bent so this was an upward pull. Second test they used 12.8 bolts and the hook straightened at about 8 ton or around the capacity of the strap.
I have seen a hook straighten in a strange way. It was the rear hook on a patrol that was being used for an anchor with the driver holding the brake and the front hook being winched off. The front hook would of had 30 to 50% more load and they were identical hooks. Luckily all the gear in use was non stretchy but it still cut a tow strap

[supamu]

I've seen a hook come off the front of a courier ute, it dented our rear bumper, lucky it didn't go higher. No idea what rating the bolts were. Also saw one get straightened over the weekend, the other end of the rope shot well up past the guy towing it.

[mulover]

Thats an interesting test geeves, would like to know what the results would have been if they had of used shock loading though. It would be very interesting to do tests using shock loading and a range of hooks, bolts, and pulling angles if it was possible to do it safely.

[geeves]

The tests were done at Cookes which specialises in ropes etc. Even then the tests are carried out in a sealed vault like room for safety reasons. A good engineering shop should be able to design a jig maybe from 2 heavy plates of steel and a mechanical hammer to test the above. It would make interesting reading

[Drift]

I went this route with mine, then used the hook up top to hold the bridle.

[geeves]

For some reason loops and shackles have never been fashionable down here although they seem to be common in Britain and America. The main reasons are that they take longer to hook up to than a hook and also unless winching in which case you use the hook on the cable in the normal way you have to use a shackle to attach the strop. Its a case of the fewer components in the mix the fewer catastrophic failures

[Clarkside]

hi,just wondering if someone could post a pic of their towbar on an mu so i can see where they are attached to the chassis,im going to fabricate one at work as they are $479 for a haymen reese when i can make the exact same for about $20 in steel and paint.some detailed pics would be great when anybody has the time to do it....cheers clarkside.

[geeves]

The bumper mounting bolts on each side of the chassis are strong enough for a standard towbar but it would be wise to also pick up the mounting point for the factory hook and maybe the hidden bolt holes in the face of the rear cross member for heavy duty or if you are including a recovery point

[pig75]

Here are some i have made
This on has towed a 1000kg trailer with a falcon wagon on it with no problems

tiw0.jpg

tiw2.jpg

This one is a bit stronger

tiw1.jpg

[Clarkside]

Excellent,great help ill fabricate it tomorrow night at work cause the boss goes home early and i can get our painter to paint it afterwards cheers fellas!

[Drift]

I use the loops with a bridle attached and held up out of the way and for easy access on the hook attached to the tailgate, works very well and spreads the forces when towing across two points rather than one.

[geeves]

From the amount we can see in the pic it looks strong enough as long as they are rated loops and the mountings are up to the job. These details are not visible.

[Drift]

Ill get a couple of other pictures up, they are rated and welded on to a high standard, my friend owns a steel fabricators and they use these loops on plant equipment he also gets subcontracts from JCB so knows his stuff in the welding stakes lol
Handy friend to have, likes his whisky to

[supamu]

Drift I like your setup. I haven't seen anything like it before. I like the hook idea for storing the bridle, if it's set up right with a clip hook it would be quick and easy stropping too. Keeps the tow point more central and spreads the load. I like it.

[supamu]

You wouldn't have to dig around in the muck to find your hook either. I wonder how it would go in scrutineering for comps in NZ.

[mulover]

I don't think they would like it too much as you have to use shackles to hook it up. It is a great way though and I have seen people with this step on the front and rear.
I hate nothing more than waiting for people on a run, who have to dig for tow hooks (personal hate, no offence intended).
A company called RUD in Australia do some very cool bolt on solid and rotating/swiveling hooks that are usually used on earth moving equipment. Some of them are rated up to 8000kg, and probably have a minimum of 1.5 safety factor, not sure how they would go with shock loading though.

[geeves]

If the hooks are the ones I think you mean they are weld on not bolt.
There are so many people in the 4wd scene that can do a basic weld and would attempt to weld one of these without knowing the metal they are welding to well enough to guarantee a good safe weld. Even the professionals might struggle getting these to weld to a 4wd chassis perfectly every time and there are only 2 ways of testing the weld.
1 cut it in half
2 xray
It is very hard to weld dissimilar metals which is why all the powers that be demand bolt on hooks.

[mulover]

RUD do bolt on and weld on ones, I've never seen them in NZ before.

[sprey]

Well to add to this topic my vx came with a stock tow hook thing.
Anyway i went while ago to get a tow hook made up and the guy at the 4x4 shop said nah it looks like a bumper hook. I wasnt soo convinced, Anyhow in need to take off my rear bumper to install my custom tow hitch. I thought id have a look at the hook properly.
Weirdly enough its fully attached to the chassis not a bumper. In a another way of putting it my vx doesnt have bumpers it just has cladding that is supported my little metal braces etc that is shown is the pics.

Well to get to the point about the hook. Its over 5mm thick. Is mounted to the end of the chassis rail with to bolts that have captive nuts. and also a nut inside the hook and a little welded piece that hooks onto the chassis

The first pic here is a pic of the hook, you can see the little bit that is hooked into the chassis it self

This picture you can see the bolt underneath

As well as the inside of the hook it is like double joined the thicker side is around 5mm
And in this pic here you can see the two big bolts that are bolted into the end of the chassis with captive nuts

And here just a general pic of the rear of the vx, showing the 7th member and the bumper bar thing that the cladding sits on.


Anyway my question is would that hook be possibly strong enough to place a recovery hook on like this vx shown below. The vx shown below is just someones in the Us with a recovery hook on it.


I checked out Ccvc thing about mounting the hooks it did seem sufficent. But id like to get a 2nd opinion.

Note - The bottom hole on the hook is quite large. Larger than 12mm so would need to be filled in and redrilled for the hook. On the black vx up top hes just basicaly bolted his on and still prob has a big gap etc

Cheers
Aaron

[jezza]

It looks like a factory tow hook not a rated recovery hook