What are the strongest 5/8" hitch pins for recovery use?

[douglastic]

Mine weighs over 6300lb empty, some get north of 7500lb.
I appreciate the words of caution, always good to be safe!

Here is a pic of the LR3 rear point (someone painted theirs yellow - which more clearly shows it's beefiness)

 

[Metcalf]

Mine weighs over 6300lb empty, some get north of 7500lb.
I appreciate the words of caution, always good to be safe!

Here is a pic of the LR3 rear point (someone painted theirs yellow - which more clearly shows it's beefiness)

That is one of the better looking OEM recovery points I have seen from the factory. The minimal cross section is still a touch concerning. For a very rough calculation of the minimum breaking strength of JUST the ring breakout section, you could do - MBS in pounds = ((cross section area x 36000 )x2). I'm guessing it is a good healthy number, but I would also want to do a little investigation of the structure behind that ring as far as support and distribution to the frame.

Personally, with the softer edges, and large hole, that is a good candidate for using a soft shackle vs a hard shackle. That would eliminate POUNDS of mass from the system.

What does the front look like?

 

[douglastic]

I have been considering soft shackles, and your input may have just convinced me to switch.

Here is the front (in red this time!) - maybe less beefy.

 

[Metcalf]

I have been considering soft shackles, and your input may have just convinced me to switch.

Here is the front (in red this time!) - maybe less beefy.

Yup, that front loop is significantly more questionable.

 

[casioqv]

A regular 5/8" hitch pin will support some 60,000lbs of shear... it's not going to be the failure point in any recovery situation. I would be very leery of swapping it out for different metals, unless you are an experienced mechanical engineer, especially if it might get used for trailering sometimes. There are many types of stresses and loads on parts that can lead to failure. For example, stronger and harder materials also tend to be more brittle and prone to cracking.

I would be more worried that some hitches aren't attached well enough to vehicle frames to support recovery loads. Factory tow eyelets are at least designed for straight pull loads, whereas a hitch might have a lot of leverage, creating incredible tension/twisting where it mounts to the frame when pulled like that. If you are lucky, you might find some stats online for the factory recovery point strength for your specific vehicle. For example, for my VW Touareg, I found online a detailed engineering analysis, and load testing showing that the factory tow eyes are sufficient for offroad recovery. You can connect a soft shackle to them, and they will fail with only the very tip breaking free, so there isn't as much projectile potential as other methods.

 

[Metcalf]

A regular 5/8" hitch pin will support some 60,000lbs of shear... it's not going to be the failure point in any recovery situation. I would be very leery of swapping it out for different metals, unless you are an experienced mechanical engineer, especially if it might get used for trailering sometimes. There are many types of stresses and loads on parts that can lead to failure. For example, stronger and harder materials also tend to be more brittle and prone to cracking.

I would be more worried that some hitches aren't attached well enough to vehicle frames to support recovery loads. Factory tow eyelets are at least designed for straight pull loads, whereas a hitch might have a lot of leverage, creating incredible tension/twisting where it mounts to the frame when pulled like that. If you are lucky, you might find some stats online for the factory recovery point strength for your specific vehicle. For example, for my VW Touareg, I found online a detailed engineering analysis, and load testing showing that the factory tow eyes are sufficient for offroad recovery. You can connect a soft shackle to them, and they will fail with only the very tip breaking free, so there isn't as much projectile potential as other methods.

That was a neat study, but recovery rarely happens in a straight line. The leverage on those tow eyes always makes me nervous.

As far as receiver hitches.....they are probably one of the better designed structures on a vehicle as far as towing/recovery loads. They are expected to live their entire life with a weight pulling in at least two directions for a few million cycles. I honestly haven't seen very many oem, or even aftermarket supplier, receiver hitch sub-assemblies fail when properly installed. I do always try and make sure all the bolts are still in them and make sure they at least pass the wiggle test for tightness. Beyond that....it's always good practice to inspect for cracked welds and heavy rust if it is not your own vehicle. Anything can be abused and fail. When drastically abused, they usually bend the main cross tube first as a good indicator they have been overloaded.

 

[casioqv]

recovery rarely happens in a straight line.

That is a great point. I think common sense applies- a slightly off center pull is probably fine for a really heavy duty tow eye, especially if shimmed to put it in the correct orientation. I think the same applies to the hitch- like you said, check the conditions, and the design. Some hitches bolt with a lot of leverage angle to the bolts. Towing loads are different- much more cycles, but a lot less force.

On my vehicle, I was able to replace the factory steel frame the tow eye screws into, as well as the tow eye itself with an aftermarket system made to convert them for recovery points.

 

[Metcalf]

That is a great point. I think common sense applies- a slightly off center pull is probably fine for a really heavy duty tow eye, especially if shimmed to put it in the correct orientation. I think the same applies to the hitch- like you said, check the conditions, and the design. Some hitches bolt with a lot of leverage angle to the bolts. Towing loads are different- much more cycles, but a lot less force.

On my vehicle, I was able to replace the factory steel frame the tow eye screws into, as well as the tow eye itself with an aftermarket system made to convert them for recovery points.

That is an interesting recovery point you have there. All that structure coming down to a single round threaded cross section that will see high bending loads doesn't look like the best plan to me. Bolts typically don't like being loaded in bending. The roots of the treads cause lots of places for fatigue cracks to start. The rest of the structure looks great. Can you bring the 'tube' section much further forward? That increased diameter and reduction in bending will help a ton. Perhaps even find something that will allow connecting to the tube eliminating the threaded/welded adapter completely?

 

[casioqv]

That is an interesting recovery point you have there. All that structure coming down to a single round threaded cross section that will see high bending loads doesn't look like the best plan to me. Bolts typically don't like being loaded in bending. The roots of the treads cause lots of places for fatigue cracks to start. The rest of the structure looks great. Can you bring the 'tube' section much further forward? That increased diameter and reduction in bending will help a ton. Perhaps even find something that will allow connecting to the tube eliminating the threaded/welded adapter completely?

I didn't make or design that, it's a product from Eurowise Offroad. I would say it's the "low end" product, trying to build something that works from inside a factory plastic bumper cover and is still compatible with the factory tow eyes- they also sell a stronger solution that replaces the entire bumper and has more traditional recovery points welded on. Those are good points about potential weaknesses. I think for my use case it will work fine as is- relatively light offroading, and only using it for linear pulls where I double up the winch line with a snatch block.

 

[Metcalf]

I didn't make or design that, it's a product from Eurowise Offroad. I would say it's the "low end" product, trying to build something that works from inside a factory plastic bumper cover and is still compatible with the factory tow eyes- they also sell a stronger solution that replaces the entire bumper and has more traditional recovery points welded on. Those are good points about potential weaknesses. I think for my use case it will work fine as is- relatively light offroading, and only using it for linear pulls where I double up the winch line with a snatch block.

Bee Safe out there. Winch recovery isn't going to be in a straight line either. The ability to have a recovery point work for off line pulls is fundamental.

 

[Ugly1]

Hmm. This idea that a 30klbish MBS synthetic recovery line can be thought of as a fuse, while using a factory class IV hitch that fails somewhere under 25klb's, seems a bit flawed. Even the class V I'm looking at will be barely enough for the dynamic ropee I'm looking at. The safety margin appears to be around 2X per this testing. The hitch pin seems unaffected in these tests.

 

[Metcalf]

Hmm. This idea that a 30klbish MBS synthetic recovery line can be thought of as a fuse, while using a factory class IV hitch that fails somewhere under 25klb's, seems a bit flawed. Even the class V I'm looking at will be barely enough for the dynamic ropee I'm looking at. The safety margin appears to be around 2X per this testing. The hitch pin seems unaffected in these tests.

Dynamic ropes should not be operated anywhere near their MBS, just like any other piece of recovery gear. There has to be SOME acceptable factor of safety.....what the FOS for drag recovery is where things get murky. If we try and use something like overhead lifting 4-6:1, you will hit a wall once you have to connect anything to the vehicle. There are very very few 'RATED' recovery points on vehicles. Using something like 2-3:1 is probably going to give us a more rounded system.

The trailer hitch in this video generally failed exactly like I would suspect with the center bar folding before being ripped completely off. Though it looks 'rough' in the video.....this is a pretty 'good' failure as it gives some really good visual indicators before finally letting go completely. There are very few other structures on a vehicle that are going to fail as well as this.

Is the 24000lb+ number underwhelming on some levels, sure, but I wouldn't get too hung up on it. I'd suspect that hitch had a full and long service life also including breaking some straps in the earlier videos.

You can try to build something even 'stronger' but that is a slippery slope overall as it will just move the potential failure further up the the assembly. I've seen more than one frame turned into a diamond because of uneven loading. Most modern frames are designed to have crumple zones too these days.

As they mentioned in the video, NOT using a huge tow strap/rope may be a viable way to go. The 'magic' in most kinetic ropes goes away quickly if you use a rope that is too big.....or you pull on it too hard. There is a smaller window of acceptable use than most people think. Generally speaking, they are the most handy and useful for a lightly stuck vehicle that needs assistance.....not for HARD recovery work.

Good luck on finding the right system for you. Bee Safe.

 

[casioqv]

Bee Safe out there. Winch recovery isn't going to be in a straight line either. The ability to have a recovery point work for off line pulls is fundamental.

This is a good point, I think you're right, that my recovery points are not safe enough for hard off line pulls, and will think about a plan to deal with that. In current form, I suppose it would be safer, if necessary, to do an off line pull from the winch clip or hitch only. I am also thinking that indexing the eye to the pull direction, and using a bridle to pull from both eyes at once would be safer.

 

[Metcalf]

This is a good point, I think you're right, that my recovery points are not safe enough for hard off line pulls, and will think about a plan to deal with that. In current form, I suppose it would be safer, if necessary, to do an off line pull from the winch clip or hitch only. I am also thinking that indexing the eye to the pull direction, and using a bridle to pull from both eyes at once would be safer.

A bridle is a solid idea to spread the load out, just make sure to make it's length long enough to remove the majority of the induced angle. I generally prefer an independent leg bridle where if one side was to fail, the other side is retained ( vs say an equalizing bridle where one leg can slip out if one was to fail ).

 

[Metcalf]

Which sort of defeats the purpose of a bridle unless pulling force is always straight on.

The legs of the bridle can always be different lengths to allow equal loading while pulling off line.