Im going to bring this back up as Im closer to buying line now. Whats the difference between the 5/16" Superline XD and the Superline? I think Ill be going with a tube thimble that way I have the option of a hook or running a shackle.
Superline is a rope that has been heated and pre-stretched, the fibers elongate and shrink in diameter giving the entire rope a smaller diameter. This is why we can have a 5/16ths Superline that is rated to 21,000 lbs vs a 5/16ths basic rope rated at 13,000 lbs. Another advantage to these ropes is that you get a much denser and tighter package, because of the way the rope is stretched during the manufacturing process. This protects the rope better because it is less likely to snag on a tree limb, rock, or anything else it might drag over. The rope also is less prone to having grit work its way between the fibers which can potentially degrade the line.
Superline XD has Superline at its core with a tightly woven cover of sk75 Dyneema (the fiber that all of our winch ropes are comprised of) over the entire line. This adds extra UV and abrasion resistance and at the same time gives you a rope that will last longer then normal synthetics.
Last week I had a Superline XD sent in that was purchased in 2005. The hook that was on the rope seized up but the rope was still in good shape, after we put a new hook on and examined the rope I sent it back out. Five years old and I wouldn't hesitate to run it for another 3 to 4 at least.
-Alex