a thorough presentation of climbing rope characteristics?


Original Post
bernard wolfe · · birmingham, al · Joined Jan 2007 · Points: 110

I'm looking for a comprehensive presentation/discussion of the various technical dynamic climbing rope performance measurements (static elongation, impact force, etc).

There are several of these kinds of presentations findable via a web search and all the ones that turned up in my initial effort of looking ranged from average to poor in terms of presenting the information.

What i'm looking for is something thorough and preferably something that also provides comparative data to consider.....ranges for the various performance characteristics (i.e., helping the reader use the data catagories to place the performance of any particular brand of rope between that of say, a steel cable versus a rubber band).

Anybody know of a good quality presentation on this topic?

Mike Slavens · · Houston, TX · Joined Jan 2009 · Points: 35

Richard Goldstone's (rgold) overview:
http://4sport.ua/_upl/2/1404/StandardEqn.pdf

A more complex model:
http://www.sigmadewe.com/bergsportphysik.html?&L=1

You aren't going to find anything that compares climbing ropes to steel cable or rubber bands because a rope doesn't act like those things. You would be comparing apples to oranges. Climbing ropes have complex dampening where steel cables and rubber bands both act like simple springs.

It is also of limited value to compare rope characteristics particularly to materials other than ropes. All these charecteristics are based on the conventional UIAA test which is very "worst case" compared to real world falls/catches.

Your best bet is to read the rgold overview, and run some of the numbers yourself on steel cable and rubber band. Then search the forums for Fall Factor discussions. All rope manufacturers list their UIAA rope test data.

John Barritt · · OKC · Joined Oct 2016 · Points: 888

Do not attempt to climb on rubber bands! JB

Marc801 C · · Sandy, Utah · Joined Feb 2014 · Points: 0

OP, what is the question you are really trying to answer?

Jim Titt · · Germany · Joined Nov 2009 · Points: 0

It´s also worth noting that all the values are for new ropes, tested the first time. There are scanty results for older ropes available, that is we don´t know if a lower-impact force rope turns into a higher one after the first fall.
Experientially and from testing we know that some ropes turn into bone-jarring cables and others into slobby things. All we know is all ropes have higher impact forces after a number of falls.
The belayer/belay device and the amount of friction throught the gear make more difference to the forces involved than any rope characteristics.

bernard wolfe · · birmingham, al · Joined Jan 2007 · Points: 110

i used to think i had resolved an understanding of the common rope performance statistics in my mind......then i tried explaining the ideas to a friend who is considering buying their first rope and realized i didn't know as much as i thought i did. Plus, the statistic total elongation and things like the unit weight of a rope and sheath slippage were ideas i had not considered in times past. Seems like those weren't advertised as prominently way back when....and percent elongation, impact force, and number of falls (UIAA failure test criteria) were maybe the focus.

So i went searching for some comprehensive presentation of evaluating ropes and have not been able to find any one source i feel does a good job. Its one thing to present data on any one rope....but if you have no feel for what the data means in qualitative terms, i think it is perhaps more effective to present a range of data in order to make a comparative evaluation. Hence my steel cable and rubber band notion......which of course was meant figuratively.

eli poss · · Durango, Co · Joined May 2014 · Points: 136

From the perspective of the consumer, the UIAA fall test data that manufacturers publish paints a decent picture if you understand what the data means.

The impact force, # of falls, and sheath/core % gives you a good idea of how the core will hold up.
The weight along with diameter will tell you how tightly woven rope is, which plays a role in how the rope handles.
The sheath%, weight, and weave tightness will gives you an idea of how the sheath will hold up to abrasion and cutting resistance.

What else does the consumer need to know in order to make an informed decision on what rope to buy?

dave custer · · Unknown Hometown · Joined Nov 2010 · Points: 770

ROPES ››› a guide for climbers and mountaineers
Available at the
https://www.thebmc.co.uk/bmc-technical-advice-booklets
page.

Guideline #1: Don't be a jerk.

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