winch recovery from a hitch pin
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Nope… In my test case, the 20mm flat bar with the hole in it where the ball mounts, bent. AS4177 specifies that the mounting face of the ball needs to sit on a flat surface with a min diameter of 60mm, from memory. This was no longer the case, so the “friction” force between the tongue face and the ball face was drastically reduced and the shank was no longer in shear. The tongue bending occurred due to the force acting on the centre of the ball having a 50mm moment arm on the tongue.
The load case that @A4B describes is different. With a shackle though the hole where the ball would normally mount, the tongue would hardly ever see a moment or bending force as the load is not 50mm offset, as it is with a towball.
The only time the J-pin could ever bend, is if you fit the pin through the strap. If you use a towbar tongue without a towball, it’s the same as using a dedicated recovery hitch. A recovery hitch is just a lot easier because no one carries the tools needed to remove a towball with them all the time and getting that big nut off can be a challenge, especially if it’s been on the tongue for a while.
@AndrieK good applied mechanics (stress analysis) lesson.
Recovery from "Rear" of vehicle, prefer to use Recovery Hitch and Rated Shackle(hitch pin thru hitch block_double shear). Captivate eye of soft sling positively so unable to slide off or release (typical security for all recovery link points).
Could use tree protector but prefer use rated soft shackle when using a rated shackle as per pic.
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Recovery from "Rear" of vehicle, prefer to use Recovery Hitch and Rated Shackle(hitch pin thru hitch block_double shear). Captivate eye of soft sling positively so unable to slide off or release (typical security for all recovery link points).
Could use tree protector but prefer use rated soft shackle when using a rated shackle as per pic.
I have also seen the pin bend when it has been used directly to a snatch strap so it can't be that uncommon. I'd still be quite happy to winch from it even though I wouldn't use the bare pin to snatch. I have repeatedly used the tow hitch for snatching with the towball replaced by a shackle as mentioned by A4B and that worked fine with no damage to the pin or tow hitch.
DON'T remove the towball & put a shackle through the hole for a snatch recovery. A young guy in Sydney was seriously injured a few years ago doing this. The weld between the tube & tongue let go & he wore the shackle and hitch tongue in the head. The hitch is designed for towing, not snatching.
Tow bars are designed for towing, not snatching and usually have exactly the same rating as the hitch so why is it OK to snatch from the tow bar but not the hitch?
Slightly off topic but you are 100% correct with the towbar & hitch rating which coincidentally is something very few people fully understand the implications of.
When a towbar is certified, the towball position relative to the hitch pin automatically forms part of the certification. In other words, if you replace the hitch / tongue with one that changes the ball position (e.g. a drop hitch) you invalidate the towbar’s compliance, unless if the towbar’s certification documentation specifies different certified ball position(s) and your replacement hitch conforms to the specification.
So just because your towbar is certified to tow 3500kg and the hitch you just bought from Supercheap Auto is also rated at 3500kg, it does not automatically mean that the combination is certified to tow 3500kg.
Using a replacement hitch is a massive risk because if ANYTHING fails, the OEM, towbar manufacturer, hitch manufacturer and ball manufacturer will all plead innocent and point fingers at each other and you’ll be caught in the middle.
Back on topic and to @62woollybugger’s point, snatching off the hitch just introduces more possible critical points of failure because it is an additional welded structure.
I had a sense of deja vu with this subject and sure enough we have been down this road before. We have different needs and use different solutions.
Tow bar
Hi Team. I'm chasing up some ideas for rear recovery points. I am seeking the experience and knowledge of the members here to work through the pros and cons of having no tow bar. Currently my GU doesn't have a tow bar. I won't be towing, ever. To save on the expense of buying and fitting a tow...
www.patrol4x4.com
Wow! Your memory is a lot better than mine.I had a sense of deja vu with this subject and sure enough we have been down this road before. We have different needs and use different solutions.
Tow bar
Hi Team. I'm chasing up some ideas for rear recovery points. I am seeking the experience and knowledge of the members here to work through the pros and cons of having no tow bar. Currently my GU doesn't have a tow bar. I won't be towing, ever. To save on the expense of buying and fitting a tow...
Can’t remember writing that, but it seems like my point of view hasn’t changed much.
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32 Posts
Just take precautions if something does snap, place something heavy on whatever your hitching off so if it snaps the force goes to the ground, not your head,
use wireless winch controls to be far out of the way, if not put your bonnet up.
always imagine that whatever you’re adding thousands of KG of force too is going to become a missile any second.
use wireless winch controls to be far out of the way, if not put your bonnet up.
always imagine that whatever you’re adding thousands of KG of force too is going to become a missile any second.
It's prob the strongest point to winch or snatch from. The towbar has the load spread across the chassis. Don't get me started on those aftermarket recovery points that are a held in with a couple of bolts and sold as a must have 4wd accessory
Use a properly rated D shackle either thru the hole where the tow bar was fitted or better still use a hitch that fits into the receiver with a proper att on it.
Don't use the pin inside the hitch.
1. They can bend
2. They can break
3. The strap where it exits the hitch can get damaged by recovery forces at the hitch opening. It might look like a straight pull but any off centre will compromise any strap.
4. A hitch pin is in double shear where it contacts the hitch and the receiver. Prob up to about 60tons plus to shear it, bending loads from a strap on the pin can make it bend/snap at loads a lot less than shear loads.
In a past life working at 2 reputable 4wd and recovery gear companies for many years in a technical/testing role I can attest to this.
The arguments re using tow balls are not valid, you cannot see any induced stress points or weakness caused by a trailer rocking around on the ball.
You do not know its state of health. Don't do it!
Also the ball is subject to bending loads not shear loads.
Don't use the pin inside the hitch.
1. They can bend
2. They can break
3. The strap where it exits the hitch can get damaged by recovery forces at the hitch opening. It might look like a straight pull but any off centre will compromise any strap.
4. A hitch pin is in double shear where it contacts the hitch and the receiver. Prob up to about 60tons plus to shear it, bending loads from a strap on the pin can make it bend/snap at loads a lot less than shear loads.
In a past life working at 2 reputable 4wd and recovery gear companies for many years in a technical/testing role I can attest to this.
The arguments re using tow balls are not valid, you cannot see any induced stress points or weakness caused by a trailer rocking around on the ball.
You do not know its state of health. Don't do it!
Also the ball is subject to bending loads not shear loads.
Well said. Courtesy of my son this is the last pin I saw broken. A 300 hp tug might not help. But you can see where the left hand hole has let go as well.
Something that hasn't been mentioned here is the difference between WINCHING and SNATCHING. Most winches are rated between 3900kg and 5000kg. Snatch straps are usually rated from 8000kg and up.
Winching recovery a is a dead weight direct pull with the force being roughly 1:1 (weight of vehicle - 2500kg - 3000kg). Even using a snatch block, applies the same force at the shackle connection of the snatch block, however reduces the force on the winch itself. This is best to use when your winch is on the lower end of weight rating.
Snatch recovery is a kinetic weight pull, and the force is roughly 1:3 (3 times weight of vehicle - 7500kg - 9000kg).
I personally have - 12m x 12,000kg snatch strap, 4,300kg winch (dyneema rope), snatch block and hitch receiver with 4.5T shackle. I always try to winch using the snatch block.
Winching recovery a is a dead weight direct pull with the force being roughly 1:1 (weight of vehicle - 2500kg - 3000kg). Even using a snatch block, applies the same force at the shackle connection of the snatch block, however reduces the force on the winch itself. This is best to use when your winch is on the lower end of weight rating.
Snatch recovery is a kinetic weight pull, and the force is roughly 1:3 (3 times weight of vehicle - 7500kg - 9000kg).
I personally have - 12m x 12,000kg snatch strap, 4,300kg winch (dyneema rope), snatch block and hitch receiver with 4.5T shackle. I always try to winch using the snatch block.
Soft shackles are easily damaged when used against a sharp edge. Some recovery hitches have a radiused edge on their holes for this reason but many do not. Soft shackles are best used for joining ropes and straps together.
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