Thread: Rear recovery hook

Whats wrong with putting a bow shackle through the tow ball hole?

Originally Posted by BigJon

There is no way on Gods green earth that the towball is stronger to snatch from than the receiver pin.

For starters the pin is supported at each end, the ball isn't.

The pin is one size through the stress zone, the ball changes shape drastically (stress raisers).

Do the maths.
Perception is often at odds with reality. Here're some FEA plots to prove it.

I did it last weekend with no problems.

I think if you did lots of heavy snatching it could stretch the hole rendering it unsafe / useless for putting a towball bach.

Originally Posted by BigJon

I did it last weekend with no problems.

I think if you did lots of heavy snatching it could stretch the hole rendering it unsafe / useless for putting a towball bach.

I've seen people snatch from towballs with no problems. It doesn't make it good practice.

Your average snatch strap is supposed to have an 8,000kg minimum breaking load, the loads shown above are just over 5,000kg and already way beyond the strength of the pin.

You were probably lucky and needed far lower forces to get your vehicle unstuck, but hopefully next time you'll think about it.

Originally Posted by Ytt105

Whats wrong with putting a bow shackle through the tow ball hole?

That's not as strong as a receiver with a shackle, but it's much stronger than just using the pin.

So what is the best solution for a rear recovery point?

A shackle mounted on the rear crossmember where they join to the main rails?

Surely a snatch strap would "spread" its load over the pin given the width of the snatch strap. Also as the strap is threaded down the tube the load/pull would be at 90 degrees to the pin (straight).

I'm sure I've seen this discussed several times before, probably on other forums and from memory the issue was always that if you could "guarantee" that the strap pulled across the full width of the pin then you wouldn't bend it as you were still utilising the shear strength of the pin. However, if the pull ended up being more concentrated towards the middle of the pin then there is a risk you could bend it. Personally I would have thought for $50 it was worth having a proper hitch receiver/shackle set-up rather than having to deal with all the crap that might get up inside the hitch receiver?

I'm interested in this comment:

Originally Posted by Tank

That's the correct one to get, when fitted to towbar the shackle pin will be vertical allowing it to align with direction of pull, Regards Frank.

Does the orientation really matter? I would have thought that there's more chance of being able to pull in a straight line but height difference is less controlable, so having the shackle pin horizontal might be better? Either way, I suspect nothing is perfect but using a bow shackle would allow the strap eye to move?

cheers, Andy

Originally Posted by scott oz

Surely a snatch strap would "spread" its load over the pin given the width of the snatch strap. Also as the strap is threaded down the tube the load/pull would be at 90 degrees to the pin (straight).

As soon as the pin gets any flex in it, the strap heads straight for the centre. While the strop eye does spread the load over some of the pin width, it's not enough to change it into a good idea.

Originally Posted by AndyRevill

Does the orientation really matter? I would have thought that there's more chance of being able to pull in a straight line but height difference is less controlable, so having the shackle pin horizontal might be better? Either way, I suspect nothing is perfect but using a bow shackle would allow the strap eye to move?

cheers, Andy

I would go for a vertical eye (so the shackle can pivot up and down), but a thin enough plate with a big enough hole that the shackle can still align. Making the plate as wide as the shackle can take and a close fit is counter productive for such a part.