D-ring shackle ratings explained - be weary of cheap Amazon shackles!

#1
Was confused by the various 'ratings' I saw on different shackles, ended up doing some research to understand, figured I'd share - I'm sure others will find this useful.

Amazon and other offroad sites are full of cheap D-shackles. You can get them for less than 10 bucks. However not all shackles are created equal, even if the 'rating' on the shackles makes it appear so.

Lets take these shackles on Amazon as an example: FieryRed 3/4" D Ring Shackle (2 Pack) 22,046Ibs Break Strength

To be considered 'rated' a shackle must have the WLL (working load limit) listed on the shackle. And these, like all 3/4" D-ring shackles are standardized at a WLL of 4-3/4 ton (4.75 *metric* tons) - this is equivalent to 10,471 lbs.

However, different manufacturers use different quality materials and the actual failure-rating of shackles with the same WLL of 4.75ton varies widely. This failure point is expressed as a ratio to WLL and referred to as the Safety Factor. When the above shackles say 22,046lbs failure point, that means that their Safety Factor is 2.1:1 (22,046lbs / 10,471 lbs).

A safety factor of 2:1 is actually pretty poor as far as shackles go and doesn't give you much room for error. The stress put on recovery gear is far far higher than the vehicle weight when any sort of dynamic forces are involved. So if you have a 6000 lbs truck, you can easily be putting x3 that if the vehicle jerks/slips. Well, 6,000lbs*3 is 18,000 and that's below the listed 22,046 lbs failure point you say, no problem, right? Actually NO, the problem is, if a shackle is ever side-loaded (45 degrees from straight pull) it loses 30% of it's WLL! If you side load a shackle fully side-ways (90 degrees) it drops 50% of it's WLL. To have a shackle rotate on your anchor in a jerking recovery situation such as when using a snatch strap is pretty easy. So suddenly your failure point is 22,046 minus 30% = 15,400lbs. Or if it's 90 degrees side loaded you get 22,046 minus 50% = 11023lbs. This is below the 18,000 lbs force your vehicle is putting at the shackles. SNAP! This is why these cheap shackles DO fail on people...

If you look at high-quality shackles such as those made by Crosby or Columbus McKinnon, they have a Safety Factor of 5:1 or 6:1. This means that they fail at 10,471*5 = 52,000 lbs!! Lots of safety margin for any sort of 4x4 recovery. That's why these are actually rated for rigging work. Sure, they're a bit more expensive, 30$ a pop, but the way higher safety margin is worth the extra 15$ I think. If this is resonating with you, just fyi: Factor55.com sells Crosby shackles which are epoxy powder coated if you like nice black or red shackles.

Just food for thought, figured I'd share so others benefit and can make an informed decisions.
 

DaveInDenver

Expedition Leader
#2
In the U.S. ASME B30.26 is what drives shackle standards. In that spec the minimum design factor for a shackle up to 150 tons WLL (in ASME standards this is U.S. Customary tons e.g. 3.25t is 6,500 lb) is 5:1 and they must be proof tested individually to a minimum of 2 times and a maximum of 2.2 times their rated load. A reputable manufacturer will state their design factor. For example Crosby for the G209 ultimate (design factor) is 6 x WLL and they proof to 2 x WLL.

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#3
For metal shackles: Crosby, CM, Van Beest. Nothing else is allowed on my truck. Shackles are cheap enough and important enough that they’re a foolish place to try to save a buck.


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#5
Something inferior with Gunnebo ? Perhaps jingoistic muckrakery prohibits using their products ??
It’s easier for me to remember the three manufacturers I trust that I can get locally and am likely to come across in the field than it is to find and remember EVERY quality manufacturer out there.


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DaveInDenver

Expedition Leader
#6
Something inferior with Gunnebo ? Perhaps jingoistic muckrakery prohibits using their products ??
I believe Crosby (red), Gunnebo (yellow or brown pin), Columbus McKinnon (CM, usually orange), Campbell (blue) or Van Beest (green pins) are all accepted as good quality, but correct if that's wrong or incomplete. Probably need to trust the source to avoid counterfeits, too.
 
#7
Has anyone ever seen a shackle failure in real life outside of a test situation?

Just looking at the rest of the equipment used in recovery (3/8 steel or synthetic cable, 1/2" bolts, 1/4" steel bumpers), a 3/4" steel shackle seems like the least likely item to fail. This test seems to confirm that even a non-US brand shackle is probably more than strong enough to handle the winching loads most people see or can generate with a typical 8-12k winch.

http://www.exploringoverland.com/ov...8/4/11/shackle-destruction-test-and-thoughts-
 
#8
Has anyone ever seen a shackle failure in real life outside of a test situation?

Just looking at the rest of the equipment used in recovery (3/8 steel or synthetic cable, 1/2" bolts, 1/4" steel bumpers), a 3/4" steel shackle seems like the least likely item to fail. This test seems to confirm that even a non-US brand shackle is probably more than strong enough to handle the winching loads most people see or can generate with a typical 8-12k winch.

http://www.exploringoverland.com/ov...8/4/11/shackle-destruction-test-and-thoughts-
I don't have much personal experience with vehicle recovery, but I think in the real world you're more likely to have peak shock loads that far exceed the weight of the vehicles involved. As opposed to the slow deliberate controlled pull of the failure testing in the video. Maybe with winching you have more control, but these same shackles could be used for a tow strap too, and that's where you might want to opt for overkill on the weight ratings.
 
#9
Has anyone ever seen a shackle failure in real life outside of a test situation?

Just looking at the rest of the equipment used in recovery (3/8 steel or synthetic cable, 1/2" bolts, 1/4" steel bumpers), a 3/4" steel shackle seems like the least likely item to fail. This test seems to confirm that even a non-US brand shackle is probably more than strong enough to handle the winching loads most people see or can generate with a typical 8-12k winch.

http://www.exploringoverland.com/ov...8/4/11/shackle-destruction-test-and-thoughts-
A lot of these destructive tests pull the shackle to complete tensile failure. What one should really be concerned with is yield strength, which depending on the material and manufacturing process could be much lower than the tensile strength of the shackle. A shackle that can’t be taken apart after a hard pull isn’t much use. Not as sexy of a what-if as a complete tensile failure, but it’s worth considering.


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TernOverland

Supporting Sponsor Ternoverland.com
#10
I've never actually seen any shackle that was properly sized for the job break. As mentioned, avoiding shock loads goes a long way, and you should do that anyway. You should always have a stretching recovery strap in there if heavy shock loads are anticipated.
 

Swede.

New member
#11
I believe Crosby (red), Gunnebo (yellow or brown pin), Columbus McKinnon (CM, usually orange), Campbell (blue) or Van Beest (green pins) are all accepted as good quality, but correct if that's wrong or incomplete. Probably need to trust the source to avoid counterfeits, too.
That's some very useful information 'DaveInDenver'!
 

dwh

Tail-End Charlie
#12
Actually NO, the problem is, if a shackle is ever side-loaded (45 degrees from straight pull) it loses 30% of it's WLL! If you side load a shackle fully side-ways (90 degrees) it drops 50% of it's WLL. To have a shackle rotate on your anchor in a jerking recovery situation such as when using a snatch strap is pretty easy. So suddenly your failure point is 22,046 minus 30% = 15,400lbs. Or if it's 90 degrees side loaded you get 22,046 minus 50% = 11023lbs.
I didn't notice this the first time I read this last year, but reading it again I see what looks like an error in the math. (Don't know for sure if it's an error or not...I'm not an expert on shackles. I'm just going by what was posted.)

Losing 50% of WLL due to side loading would be 10k lbs. (WLL) x .5 = 5k - not 22k lbs. (break load) times .5 = 11k.
 
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#14
Does the side load de-rating apply to shackles that use a bolt/nut type pin instead of the more common threaded pin/eye? I'd imagine there might still be a de-rating factor, but is it as much? I'm guessing most of the de-rating comes from the lower holding strength of the pin/eye threads in a tension scenario when the shackle tries to be pulled apart with a side load.

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