Why for Prussics but not Bridges

[rfwoodvt]

This is a spin off of my recent replacement bridge posting.

why for is a technora or other aramid fibers falling apart as bridges but not as prussic cords?

I would assume that the self abrasion would come into play on the prussics but the question still remains.

Thots?

 

[Blinky]

I can't say with even a shred of authority but the bending stress on a bridge means that more flexible fiber will wear better and heat shouldn't be an issue. Other than tension, bending is the primary stress on a bridge.

With a hitch cord the primary stress other than tension is heat and that's what the aramid fibers do well. When we talk about self abrasion in aramids I wonder whether we really mean bending and fatigue.

Anyway, Technora makes a killer hitch cord that seems to last a long time. I remember going through a Tenex cord in as little as two weeks and my current one made with 8mm Ocean is 6 month old.

I've taken the jacket off of a few of my HRC hitches and the Vectran core looked pretty much like it did when I spliced them up.
My bridge? Ehhh... not so much. The hitches were only a few months old; The bridge, about 20 months.

 

[Norm_Hall]

I think Blinky hit the nail on the head.
In a bridge, the fibers are being more compressed against each other with full body/gear weight.
In a hitch cord, it's more surface on surface contact/wear, with half body/gear weight.
This is more of a question for the technical staff at the rope manufacturers.

 

[rfwoodvt]

Taht does make sense, perhaps it is a matter of bend radius and the "rolling" motions of rings and biners along the bridge.

Wonder if a bridge pulley makes any diff?

 

[NickfromWI]

Also, every time you retie your hitch, you put the wear on a slightly different spot. The bridge gets worn pretty much at the exact spot all the time.

Also, the wear on the hitch cord is spread over a larger area.

love
Nick