Chombi,
I have four of those in my garage. The two earlier ones (~6 years) had a type of black cord that was softer and frays with use. I haven't replaced them yet, as the portion that suspends the bike never passes through the clamp, but only the pulleys, so I don't worry about it.

The two newer ones (~4 years) have a tougher nylon that hasn't frayed.

My biggest concern about using these pulley systems is that half of the bike's weight is being supported by the underside of the saddle (where the rails meet the saddle frame). I don't put any of my bikes with nice saddles (Brooks, Fujita) on these mounts, preferring to lift them upside down onto plain-Jane bike hooks.

Phil G.