recovery point ripped clean from chassis

[terryc]

Make sure you check the rating on those receiver hitch shackles. I think I've seen both 4T (SCA?)and an 8T (Repco?) on offer.

Edit; of course, I guess 4t is sufficient as tow hitch is only rated to 3T anyway. would be better to destroy the shackle than rip the tow out.

 

[Old.Tony]

+1 for checking the ratings, although I think the SCA is a 4.75T like the ARB one.

Don't get it in your head to attach the tow rope/winch extension/drag chain to the pin passed through the hitch receiver, either. You'll end up bending the pin and not being able to remove it, or having the pin tear itself out and become a missile.

Also, if you don't have one, pack a blanket or a proper recovery dampener. This should be placed over the connection between the vehicles (winch, winch extension, drag chain etc). The idea is that the blanket/dampener will slow down the cable if one end breaks, so that it doesn't do anything lethal.

 

[Scubamurph]

Thanks for the pic and info. I know what to look for now.

Murph

 

[siringo]

This is a very good thread on front recovery points. Just the fact that the factory tie point/recovery point was ripped out indicates that that exact location where that point is mounted is not too strong. I bet the factory 'hook' wasn't damaged, they look extremely strong.

If you have a bullbar fitted, the recovery point needs to sit off/away from the chassis quite a distance so any strap or cable used doesn't foul the bullbar, the length of the factory 'hook' gives this distance. I am going to contact ARB to see if attaching a recovery point to where their bullbar attaches to the chassis is an acceptable location to mount points.

It's hard to describe, pics will be alot easier.

Edit: Oops, the factory hook wasn't in use, 2, 3rd party hooks were in place.

 

[jarryd]

i have a tjm bullbar and they took mine away , went out 4wding went to put a shackle on and nothing there ! i was furious .... but after reearching i ended up getting some made up that bolt onto the chassis with lengthen high tensile bolts to where the bull bar is , my bullbar is winch made , but if i ever have to get pulled out i will use both points and an eql strap

 

[Chris C]

Hi all,

A few points I can think of after reading all of the above, looking at the pictures and spending a fair portion of the weekend under my D40 fitting an ARB deluxe bullbar.

I would not use the factory tie down/ tow point for a snatch recovery ever, the design is all wrong, the bolts are close together, and while being hi tnesile fine pitch 12mm, they would have great shear strength, but the leverage plced on the bolt by the long length of the recovery point means the force would be applied as a downward pulling force on the rear bolt, then as it fails, much more so on the front bolt. NOT GOOD.

The aftermarket recovery point shown in the first lot of photos while better, still has the same effect, but with the added issue of being offset to one side, with now twisting added to the forces applied, again not good.

An ideal recovery point would be as low profile as practical, it should be as close to the center of the chassis as practical.

The further apart the mounting bolts the better, as any twisting and leverage applied will be less with the greater distance between the bolts.

My ARB bar on the late spanish chassis uses the 2 12mm captive nuts on the underside of the chassis as part of the bullbar mount, it also uses the the 2 forward facing 12mm bolts, so a recovery point low and close to all 4 of the bar mounting point would be the best spot to place one.

I refitted the tie down point back on mine when I fitted the bar, but will be removing it as soon as I can come up with a decent design to fab up.

I will be fitting rear points off the side of the towbar, as close and as in line with the chassis as I can get, by using the towbar, the load will be spread across the chassis, through 10 12mm mounting bolts, not just two mounting bolts to the chassis.

Chris

 

[DrunkenDamo]

Bringing up the recovery hook dilemma, we got a arb bar fitted earlier this week, i was at work but got the missus to ask them to fit recovery hooks to the front as well, she was told they are still under design and don't have anything they can fit atm, i looked at the ebay ones they are all teh same i did like these though

its a shame they don't use the side bolt hole on the navs only pootrols, would be a nice bit of extra support. I have been doing a bit of research but have not seen anything that jumps out at me. I want a recovery point that i can put a shackle on aswell as having the hook there for easier recoveries under water/mud

 

[Eug]

i have reservations about the ones designed like the image you have above, the pivot point of the shackle creates a leverage on the mounting bolts. much like the chassis issues at the rear with the old design towbar which lead to a crack in the chassis rails.

i agree, some side bolts would distribute the loads much better. this is also something that's been included in the new design towbars.

just wondering if many of these recovery points include a crush tube to go between the rail walls?

 

[joe2006]

I have recovery points like the ones in the photo. There are no crush tubes and they bolt to the existing position of the tie down point on one side and in an equivalent position on the other side using the existing holes in the chassis.

They don't bolt through both sides of the chassis (top and bottom) so crush tubes are not required. I have put a plate on the inside of my chassis on the drivers side in case it wants to pull through but without removing the bulbar, could not make the plate very big. The passenger side bolts to the chassis using the existing captive nuts.

 

[Pete22]

i have reservations about the ones designed like the image you have above, the pivot point of the shackle creates a leverage on the mounting bolts. much like the chassis issues at the rear with the old design towbar which lead to a crack in the chassis rails.

i agree, some side bolts would distribute the loads much better. this is also something that's been included in the new design towbars.

just wondering if many of these recovery points include a crush tube to go between the rail walls?

So long as they are attached with high tensile bolts to the factory mounting points they will not fail. And, the turning moment is so negligible that it is not worth worrying about.

 

[180degrees]

The moments may be small but the forces would be huge you have two tonne of truck moving at what ~20km/h the kinetic energy transferred alone would be well over 30KN.

 

[Pete22]

The moments may be small but the forces would be huge you have two tonne of truck moving at what ~20km/h the kinetic energy transferred alone would be well over 30KN.

That is why you fit them with the correct bolts. Use mild steel bolts and they will let go....use the correct high tensile bolts and they will never let go. You calculation might well be true if you used a winch extension strap or other medium that doesn't stretch. Most of that force will be taken up in the "stretch" of the snatch strap. But like anything where you have high forces/loads in play - always err on the side of caution. I don't only use dampeners on my winch rope - I also use these when snatching. Has worked for me for more than 20 years with various different vehicles and I've not yet had an accident.

 

[Old.Tony]

I don't only use dampeners on my winch rope - I also use these when snatching. Has worked for me for more than 20 years with various different vehicles and I've not yet had an accident.

Can I just comment on this and say that it's one of the more common-sense things I've seen in a long time.

 

[steve1961]

I made a few calls today about this and found a few interesting things # 1 nobody is repaired to make high strength ones " ie any that don't use original captive nuts " and the reason ? They would have to be ADR compliant , and not interfere with air bag deployment , which by their rigidly and bolting through the chassis they probably would , so I look at my set up , I have an arb winch bar , which is attached to the chassis brackets with 6 1/2 inch bolts and 4 smaller ones , if one was to drill out board if the winch mount by 3 inches and use a bit of 5 mm plate behind , drilling 2 , 3/4 inch holes and using 3/4 rated eye bolts , the problem would be solved , at least for trucks fitted with arb bars

 

[180degrees]

That is why you fit them with the correct bolts. Use mild steel bolts and they will let go....use the correct high tensile bolts and they will never let go. You calculation might well be true if you used a winch extension strap or other medium that doesn't stretch. Most of that force will be taken up in the "stretch" of the snatch strap. But like anything where you have high forces/loads in play - always err on the side of caution. I don't only use dampeners on my winch rope - I also use these when snatching. Has worked for me for more than 20 years with various different vehicles and I've not yet had an accident.

All of that energy is transferred into the car being pulled out.

the energy has to go somewhere, one of newtons laws explicitly states this, if it didn't then you would a fraction of the energy needed to free the bogged vehicle being transferred, think about it, your going to have kinetic > potential > kinetic.

not doubting what you said about the bolts just saying the forces in play are enormous which is simply why one must be careful.

 

[Eug]

The concern is not the tensile of the bolts, it's the way they are mounted to the chassis. I would prefer to have the bolts pass through both walls of the chassis with a crush tube in between. Additionally, having some side bolts would help distribute the forces across the chassis box section rather than levering off just one wall.

 

[GAD]

I have got a set of recovery points for the front off roadrunneroffroad.com.au , and the problem I am having is how to mount these when the original bull bar closes off the front of the chassis . I have looked at the tie down point on the passenger side and will have to get a longer pipe as the I can't move the bolts with the breaker bar and a meter long extension . Please tell me I don't have to remove the bull bar to install the driver side point ? though I suspect the answer is I do .

 

[joe2006]

My ARB bar partially blocks the end of the chassis but it is open enough to pass a couple of plates through. The bolts pass through the recovery point, through my Brown Davis bash plate, through the chassis and through the home made plates. The nuts enter the chassis through one of the larger holes in the side of the chassis. I welded some fencing wire on the nuts and plates so they could be located and held in the chassis.

I did not use the nuts/plates and bolts supplied with the recovery points. I needed longer bolts and the nut/plates supplied would not fit through the front opening of the chassis. Replaced with HT nuts and bolts.