Old trad guy starts sport climbing ...

I got to thinking about the effect of bolt hangers on carabiners. In Scanning our buddy Craig Luebben's book Rock Climbing Anchors (http://tinyurl.com/5os5bh), he recommends replacement if you find notches or sharp grooves in your 'biners.

I tend to climb sport routes like a trad guy, with the worst load I've put on a piece being a controlled fall (as in pro at my waist). Still, I've noted the formation of some notches on a few of my 'biners.

Has anyone come across a published study on metal fatigue, the effects of falls on bolt hangers, etc.?

Cheers,
Thom

check out this link. http://www.thebmc.co.uk/Feature.aspx?id=2618

i've taken pretty big whips on plenty of bolts (and a nut, once), and i've had climbing buddies of mine fall on draws that had the wall-side biners cam in the bolts (that is, they jammed in the bolts and the sling of the draw might have been @ a 45 degree angle to the wall while the wall biner was at 90 or 100 degrees), and i still use those draws, and in fact have fallen on the same pieces of gear (always much less than factor 1) without any negative consequences. in one instance, an AMGA guide pointed out a camming draw, and when asked didn't suggest that the draw be put out of commission, just that it happens sometimes when you're sport climbing. thinking back on my experiences and the experiences of those i've climbed with, i've only ever heard of rockfall and bolts blowing as causes for super long falls, never anything gear related.

however, as with anything, if it wigs you out, don't climb on/up/down it.

the vast majority of my relatively limited experience has been on bolted routes, and i regard falling as part of the sport. sometimes, on a nice overhung route, it can be pretty thrilling, and on trad gear i've found it actually made me more confident in the pieces of metal i had jammed into the crack. enjoy those bolts, man. sometimes i miss them.

The margin of safety built into carabiners and ropes is so high, I just don't worry about that kind of thing. I'm still here...

Slipping and falling off the top of something on the descent is going to kill you before anything related to gear failure I think, with the notable exception of manufacturing defects.

Dropped gear, shallow smooth nicks, notches, dings, etc. isn't going to compromise your safety within normal limits. If the limits are abnormal, then other things are going to be a greater risk.

I'd be most worried about the effect of a notched 'biner on your rope. If there's any kind of sharp edge on the inside radius of your biners, I'd retire 'em before they have a chance to abrade your rope.

I pulled this from the BD website. They've got a bunch of good articles about interesting testing they've done in their lab.

Worn Biner—Drop Tower Test

I brought the beat-up quickdraw in to work and did a few tests.

I wasn't concerned about the ultimate strength of the rope-end biner, but rather was concerned about the sharp edge of the biner possibly cutting the sheath of the rope if someone were to fall onto that first draw. Any time I've seen a rope get "sheathed" in the field it was a combination of factors. Usually the biner has a very sharp edge (as did the biner in this case) but also, the rope is usually pinched between the sharp-edged biner and the rock.

We did a test in the drop tower using this worn biner, without pinching the rope against anything. The force of the fall was 1650lbf (over 7kN)—Note: this would be considered a gnarly fall in the field... The rope (9.4mm) did not sheath, which was good, but remember, it wasn't pinched against a rock surface—my guess is that the rope would have sustained damage if it were being pinched. An interesting thing did happen though— during the fall the basket of the gate stretched enough to allow the gate to flip to the outside of the biner. (see photo)


My guess as to how/why this happened is the following:

Partially due to the fact that the test was done with this biner as the only piece of protection in the system (as it would be on the route if someone fell just past the first bolt), there was what we call the whiplash effect, or gate flutter. As the load is impacted, the gate actually flutters open slightly, but at the right time, and just enough that really you are experiencing an open gate situation—this allowed the basket of the gate to bend slightly at the spine end (where the rope groove is). The gate flutter situation may have been more likely because the spring tension on this gate was rather weak and the rope groove of the biner reduced the cross section enough near the spine to allow the basket to deflect more (than if it wasn't rope-worn) during the gate flutter scenario.


Worn Biner—Ultimate Strength (open gate)

We then took the biner to failure (in open gate) in the tensile test machine. It still met its stamped rating of 10kN (2248lbf) (actual result was 2300lbf).





Notched Biner—Ultimate Strength (closed gate)

We also broke the bolt end biner that was worn and notched.

Rating was 28kN (6294lbf)
Actual ultimate strength was 6949lbf (30.9kN)



Sling

We then broke the sling.

Rating is 22kN (4946lbf)
It failed at 3776 (16.8kN), about typical for what I've seen of nylon slings being left on fixed routes—not really dangerous to the climber, but definitely weaker than when new.

The morals of the story:

Ramsey is sick strong—yeah, no kidding...
Worn biners can sheath ropes—more likely if the rope were to get pinched between the biner and the rock—retire biners when they get so worn as to exhibit a sharp edge.
Gate flutter really can happen.
Gate spring tension is important—make sure your biners have good smooth gate action.
Rope-worn biners and gate flutter in combination is not good...
Nylon slings get weaker when left on fixed routes—switch out old fixed gear.

Later,

KP

Jake

Thanks Jake (and to all others posting here),

This was the sort of quantitative stuff I was interested in reading about. Anecdotal evidence is fine, and it surely builds our collective body of working knowledge. Coupled with "hard data" like that on the BD site, it gives me an even higher comfort factor.

I surfed over to BD and found that section of their website. For those interested in one-click shopping, it's over here:

http://www.blackdiamondequipment.com/scene/beta/qc_kp_archiv>>>>>

Over the past 5-10 years, one of the demons that's been in the back of my head is all of the "stupid-lite" gear that's out there in climbing biking, etc., and how much it stands up to abuse. Out of the box specs can be meaningless for much of this stuff. Fortunately, for 'biners, the thin walls are still quite strong.

Cheers,
Thom

In climbing, ancedotal evidence is generally very accurate. The hard data just ends up proving the anecdotal evidence. Anecdotal EVIDENCE mind you, not theory or speculation. Climbers test this stuff in actual practice every day. Of course, sometimes you don't know if someone is telling the truth or lying or exaggerating, which is why I've seen some hideous badgering and flaming take place when someone adopts a position that is counter-intuitive to veteran experience.

Jake's links are quite quite comforting, though, to be sure, and make a great point - if the damage and wear can be destructive to the material of a rope or sling, then it should be retired, or smoothed down if possible without compromising the equipment.

Oh, and I realize that you are a trad veteran - I'm just speaking in general.

As a general rule I always clip the same biner of my quickdraws/slings into the bolts. This way if there is a slight notch it doesn't ever have a chance to touch my rope.

ditto on paul's post. it's often easy to discern the rope end of a draw from the wall end, and mine never switch. straight gate at the wall, bent at the rope. alternately, whichever end of the dogbone has a smaller loop or a rubber support thing for the biner is always my rope-side.

Amen to all! I was initially disconcerted when I saw the notches.

The first thing that occurred to me was some of the early "Aheadset" stems on bicycles clamping down on carbon steering tubes (super tricked out carbon fiber forks). Apparently, you could compromise the integrity of your steering quite easily. Of course, I wouldn't know ... my old Columbus SLX Eddy Merckx road bike from 1986 has a steel fork, thank you ;-)

In the search for lighter and lighter gear, I asked myself how thin the walls on this current generation of 35-40g 'biners are, and whether there's a parallel to the chase for lightness in bicycling.

Yes, we have collected a comprehensive body of knowledge, and lord knows, we've survived a century of climbing with this knowledge. Can you imagine the Stettners wandering into the hardware store in Estes Park back in 1927 and asking the number of falls the sisal rope they were about to buy could sustain?

I completely agree as far as reserving one side of your draw for the rope, and one for the wall.

Cheers,
Thom

GNU-
Big cheers on the classic Eddy. Steel is real baby. Picked my classic EM Corsa '92 up about 10 years ago and built it up myself. Dream ride.

About the ultra-lite biners. I picked up a bunch of Austri-Alpin super light weight biners about 8 years ago with a "1" inside a circle (like on a single rope), stamped on the spine. I picked these up while in germany. A friend told me they were ultra lights rated for 1 fall. I've never heard of this. Anyone out there have any info?

Jake