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FACTOR 55 Synthetic Rope Spool



To thimble or not to thimble – that is the question. 

First, a little bit of info on D/d ratios.

There is a common belief that a synthetic rope eye termination should possess a diameter D/d ratio in the 6-8 range. Most synthetic winch ropes come with metal thimbles providing this ratio when new. The trouble is that the metal thimbles eventually yield and collapse onto the retaining pin, thus reducing the D/d ratio considerably.

 Is this so bad? What happens to synthetic rope strength when the D/d ratio is reduced?

Luckily for us off roaders, many technical papers have been written on this by rope manufacturers and cordage experts and corresponding tests have been completed. Even when a single leg rope eye is pulled against a D/d of 1 (3/8 rope eye pulled against a 3/8 pin), the rope still retains almost all of its original strength.

Why is this?

It’s because you have the load of the pin being carried by two legs of the rope, similar to basket loading a synthetic sling. In fact, the testing standard for pull testing synthetic rope single legs is to use a shear pin in the (1.5 – 2) X d.

So what’s the bottom line, and what does this mean to us off roaders?

It means that if your rope retaining pin is smooth, and at least as big as the rope diameter or greater, you can run a soft thimble-less eye on the end of your rope and lose little to no breaking strength. We just released a rope spool with a D/d ratio of 2.6 for those who would like to run soft eyes onto the following Factor 55 products –ProLink, FlatLink, FlatLink E, Bridle, and UltraHook. GTK



This product will NOT work with ProLink XTV, ProLink XXL, or FlatLink XXL

If you currently have a metal thimble on the end of your synthetic rope, ROPE SPLICING IS REQUIRED


Here at Bigfoot Winch Ropes we CAN install the spool onto your NEW winch rope or you old winch rope.  Give us a call to work out the details.


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