Montana Overland & 4x4 Adventures

By Richard Hiltz 

How can a hard shackle rated at 9,500 pounds be stronger than a soft-shackle rated at 32,000 pounds? Easily. ~ Let me explain.

I recently watched several videos where the off-road hosts make a dangerous mistake. Regretfully, it is a common one. Each claimed a 3/8" soft-shackle with a rated breaking strength of 32,000 pounds is stronger than a 3/4" bow shackle because, they tell us, it is rated at 9,500 pounds. 

Do you see their mistake? Let's look at that a little deeper and I will explain. 

The problem is they simply do not understand the different strength ratings being used on these two devices. Without this knowledge, they are comparing apples and oranges and are making poor equipment choices and potentually unsafe recommendations.

It seems they do not understand the difference between a Working Load Limit (WLL) and a Minimum Breaking Strength (MBS) rating. 

Definitions: 

Working Load Limit (WLL) is the maximum safe force that a piece of lifting equipment, lifting device or accessory can exert to lift, suspend, or lower, a given mass without fear of breaking. Usually marked on the equipment by the manufacturer. WLL is a factor of MBS and is a safety rating.

Minimum Breaking Strength (MBS) is the minimum amount of force required to break an object. It is also referred to as tensile strength or breaking strength. Recovery equipment that is not also used in the lifting industry usually just rate their equipment with the MBS. 

A WLL is the product of Minimum Breaking Strength (MBS). To determin the WLL, you divide the MBS by the required (or desired) safety factor. (Note: items used in overhead lifting {think craines} have a legally defined min. safety factor inte U.S.) The safety factor, for a rated bow shackle, is based on either a 5:1 or 6:1 safety factor. This means the low-sounding 9,500 pound WLL is actually indicating a 47,000 or 57,000-pound Minimum Breaking Strength.  47,000 pounds sounds a bit stronger more 32,000 pounds, don’t you think?

Let's properly compare the strength of a 3/8" soft shackle to the 3/4" bow-shackle used most often in off-road recovery.

Rated 3/4" bow-shackle(7/8" pin) 

Most have a 5:1 safety factor.  Some have a 6:1 safety factor.

Working Load Limit: 4.75 Tons or 9,500 pounds  

Minimum Breaking Strength @ 5:1 safety factor: 47,000 pounds

Some higher-quality bow-shackles have a 6:1 safety factor.

3/8" soft-shackle: (Strength ratings vary a little from manufacturer to manufacturer, but I will use the number used in the videos I watched. 

This item generally does not have a WLL and is not certified for overhead lifting.

Minimum Breaking Strength claimed:  32,000 pounds

You can get soft-shackles with much higher Minimum Breaking Strength ratings than 32,000 pounds. However, many of those won't fit standard recovery points without using a bow-shackle, which defeats the claimed purpose. A 3/8" soft-shackle is generally the largest soft-shackle that will fit in a standard recovery point. The most common recovery point is made for a 3/4" shackle (with a 7/8" pin).

So now you can see how a 9,500 lbs bow-shackle is stronger than a 32,000 lbs soft-shackle.

There are some great benefits to soft-shackles. I am not saying not to use them, not even close. People just need to understand their strength ratings and how they truly compare to other recovery items.  

Strength is only one factor you should consider, but it is a factor that is often misunderstood. This small article is meant to clarify this, if only a little. Hopefully, I have done that.

Remember, neither a hard or a soft shackle is right in all situations. Both have thier own list of Pros and Cons which change depending on the specific job at hand. In general, the strength of either device may be more than enough for your uses, but my point is "more than enough strength" is NOT the same as STRONGER. Either way, both hard and soft-shackles have their proper place in the recovery world, just choose your recovery gear carefully. 

Be careful out there and Wheel Safe!!