Offroad-Express

Looking for a solution as to how the feck am I going to attach a recovery hook to the front of the truck. (I've purchased a recovery hitch/receiver to go in the rear)

There is 2 x factory tow/recovery points (about 6mm plate coming down from chassis rail welded to the rails & bolted too I believe)
There is room to drill 2 x M16 holes in each plate with at least 10mm material between holes and any edges to attach my hooks to.
Is this going to be a good way to go about things?

Hooks came of a Mitsubishi Fuso 4x4 truck (I think vehicle has a GVM of 8000 kG) These truck are used for rural fire fighting.
Bolts are 2 x HX-HD M16 x 50 Grade 10.9 Black.

I'll get photos up when I get my camera ready and it should clear this up if its like mud for you.

Heres what I mean, Just measure plates properly 7mm it is.

Assuming it is only run of the mill mild steel (Yield stess= 248Mpa & UTS=840Mpa)

Just ran some simple calcs, 16mm hole in 7mm plate is good for 27.76kN
(two holes in the plate so 5.7T (for two holes) bearing load (yeilding load)
Ultimate tensile load assuming plate UTS is 840Mpa is 10.3T per hole

M16 bolts in 10.9grade is over kill came out at 189kN min shear load.

(divide these numbers by 9.81 to get the Kg equivalent)

I just have to worry about is the way the plates are attached to the chassis rails.

Has anyone thought of safety wire / chaining their recovery equipment to the vehicle (like a trailer) when doing a recovery to midigate flying snatches & god forbid towing eyes

Hope this has helped some.

Cheers

Very interesting.

That UTS seems a little high for standard mild steel, we usually work with 350MPa steel that has a yield of around 500MPa and yield of 350MPa.

Looks like Nissan did their calcs on the tow point, thats around what the standard winch can pull by the looks of it.

Colinl wrote:Has anyone thought of safety wire / chaining their recovery equipment to the vehicle (like a trailer) when doing a recovery to midigate flying snatches & god forbid towing eyes

Interesting idea... But I would think it best to engineer the anchor points so the weakest point is the rope....I would rather break a rope than pull my truck apart...
Also some recovery hooks act like fuses as they bend straight when overloaded...

As far as snatch recoveries which tend to provide some dramatic fails .. I will try it a few times.. then its winch time.... Nice and controlled.

kbushnz wrote:

Colinl wrote:Has anyone thought of safety wire / chaining their recovery equipment to the vehicle (like a trailer) when doing a recovery to midigate flying snatches & god forbid towing eyes

Interesting idea... But I would think it best to engineer the anchor points so the weakest point is the rope....I would rather break a rope than pull my truck apart...
Also some recovery hooks act like fuses as they bend straight when overloaded...

As far as snatch recoveries which tend to provide some dramatic fails .. I will try it a few times.. then its winch time.... Nice and controlled.

I fully agree with you to have the snatch/rope as the weakest link but that's always not the case when you see these tow/snatch straps seem excessive in their ratings. (correct me if i'm wrong or if i'm too thick and blind to find them)

Just seemed logical to me to safety chain the parts that have potential to fly. even if the safety wire fails its taken a lot of force out the object already. I'm new to 4wding so trying to be a human sponge and learn as much and contribute where I can.

churchill wrote:Very interesting.

That UTS seems a little high for standard mild steel, we usually work with 350MPa steel that has a yield of around 500MPa and yield of 350MPa.

Looks like Nissan did their calcs on the tow point, thats around what the standard winch can pull by the looks of it.

GSA = Goggle strikes again.

Should have learnt this by now. Never trust what you find on google 100%

personally i wouldnt use chain as a safety device when snatching because even with reduced load a flying piece of chain is not a very nice thought at all

heres how i did mine.

Bloody awesome tweake looks bloody good! How did you get the nuts up underneath the chassis, the zinc coated ones that hold the angle to the rails though?

There should be two already there for stock recovery points?

yep, standard captive nuts. a nissan hook will bolt in but the after market ones are to short.

tweake wrote:



heres how i did mine.

I was going to suggest this too as it is what I did before I built my winch bar.

tweake wrote:yep, standard captive nuts. a nissan hook will bolt in but the after market ones are to short.

Thinking of using counter sunk Rivnuts for a onesided install.

Will post photos when I get around to it.