ASR Soft Shackle Sizing Guide
Sizing recovery gear is invariably a challenge so when a company comes out with a chart to aid in the process it’s good news. Advanced Synthetic Rigging has provided me with an early copy of their Matching ASR Soft Shackle Size to ASR Winch Lines, Winch Line Extensions & Kinetic Energy Ropes.
Using the chart you should be able to perfectly match the size of your soft shackles to synthetic winch line or kinetic recovery rope.
Note: Other companies may have different Minimum Breaking Strengthx for their products so one company’s chart does not necessarily transfer to another.
I do like the fact they give Minimum Tensile Strength (aka Minimum Breaking Strength) and Working Load Limit (WLL) for their soft shackles. Knowing these numbers we can calculate the Safety Factor (SF) they are using (see my article on Calculating Working Load Limit on Recovery Gear for more information).
To calculate the SF we divide the MBS by the WLL, 43,500 ÷ 8,700 = 5, or a Safety Factor of 5:1. This is the recommended SF for soft shackles. It’s always a good idea to make sure the company is not padding their Working Load Limit by using a lower Safety Factor (this is fairly common with some overseas manufacturers).
Since they did not provide MBS and WLL for the winch lines and kinetic recovery ropes, let’s go through a couple of examples and see how the numbers work. We’ll use the 5/16″ soft shackle for this exercise.
ASR’s 5/16″ winch line has a Minimum Breaking Strength (MBS) of 11,700lbs. The 5/16″ soft shackle, which is recommended for this size rope, has an MBS of 29,000lbs. This is exactly what we want to see, a soft shackle MBS that is higher than the winch line’s MBS.1 Now let’s have a look at a kinetic recovery rope.
Their 7/8″ kinetic recovery rope has an MBS of 28,600lb. Again, the recommended 5/16″ soft shackle looks properly sized with an MBS greater than the recovery rope.
I see a lot of people who think the soft shackle should be the same size as the kinetic recovery rope. While this might seem logical, once you go through the numbers you’ll find it’s not true. ASR doesn’t sell a 7/8″ soft shackle but the 3/4″ has a MBS of 137,000lb, which obviously is beyond overkill.
1Yes I know some off-roaders like their shackles to have a lower MBS than their winch line so they will break first. The argument being this will save the winch line. I am in the camp that says you should use your recovery gear within its limitations and you won’t have to worry about breaking anything.