Climbing anchor shock loads are a myth - human testing in Yosemite

If one bolt or cam fails on a sliding X, does the shock load create enough force to be dangerous. Many put limiter knots half way up the slings on both sides in order to limit the shock load but that reduces the strength of your sling significantly. So I use my body to see what it feels like when shock loading a Mammut dyneema climbing sling. Filmed with Bobby Hutton, Russell Travis ( / alpenglowgearco , Robbee Pitts in January 2020.
Chart of test is at 12:01
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[@HowNOT2]

Check out our new store! hownot2.store/

[@giorgiobalestrieri1431]

8:29 "do you think it's safe enough for me to attach direct?" -> looks at the 400ft drop, doesn't say anything. Legend

[@northernlights1260]

Been watching your vids and i didn't realize this wasn't your full time gig. I gotta say i really appreciate your time and money that you've spent doing experiments. I know breaking all this gear is probably pretty expensive so thanks for all your work

[@danielmerrick3000]

Thanks for doing these tests, I have wondered what the real numbers were for a long time. There have been some tests with human volunteers but the data is hard to find and not always relevant. The design forces we generally hear about (i.e. 22 kN) were not determined by measuring actual fall forces but were derived from survivable decelerations in parachute harnesses. In climbing, survivable forces are doubled to account for doubled ropes at anchor points so 11 kN is considered a limit for survivability. For a 0.8 kN (180 lb) person, 11 kN is 13.75 g’s. Yes, people in rocket sleds have survived 45+ g’s but that is front to back and supported. In a vertical harness at around 13 g’s, spinal and soft tissue injury is severe. Your guts try to exit your bottom and your spine crushes. These concepts were later incorporated into ejection seat designs. Anyway, the force requirements for climbing gear have nothing to do with the forces that can actually be generated in a fall. A #5 stopper is rated for 6 kN (1349 lb) or 3 kN at the harness and will catch most any lead fall. I’ve done instrumentation work in the past and have a couple comments to consider. To detect a dynamic signal, you need to sample at least twice the signal frequency. To determine the magnitude of that signal you need to sample at least 10 times the signal frequency. You state that your equipment samples at 500 Hz so you should be able to measure up to 50 Hz with some confidence. The natural frequency of the human column is somewhere around 10 Hz so your measurements should be fairly good. Bear in mind that digital sampling will never catch the absolute peak but you should be close enough. Personally, I would use accelerometers instead of force but both methods work. Later, Dan

[@beaniebobh1]

Hey Dan, Bobby here. Thanks for sharing your insight. We looked at the KN to G's conversion. Not coming from a very strong physics background I was unsure if the two measurements were exactly the same or if they measured slightly different things i.e. impulse vs Force. Also what accelerometer would you recommend? We would be interested in getting some input on future experiments if you are willing. [e-mail]

[@totilsom]

amazing amount of info! thank you So.. the 3K is actually the most ever that would ever happen in a fall?? (felt by the human that is)

[@julianmehnle]

​@@totilsom That number applies only to #5 micro stoppers. Larger stoppers or cams will support a higher force.

[@natetronn]

Ryan will jump off a 1000' cliff in a tire but, as soon as he's right at the anchor and dropped two feet he's scared? hahahahaha

[@HowNOT2]

Good point! I should be scared when I jump off 1000 foot cliffs also i guess hahahaha

[@zigakastelic8647]

driving fast in a highway or regional road is way scarier than on a racetrack. i guess its the same mindset here.

[@LexCCSCrewNTC]

yes this is very wierd!!

[@politykanazw2622]

It's a different Ryan

[@solsoliiss.1102]

This channel is so underrated! Thanks for the amazing videos, Ryan!

[@cornishlad97]

I am currently in the final year of a 5 year masters degree in mechanical engineering. I have also been climbing for over 12 years and am training as an outdoor climbing instructor as we speak. i weigh the better part of 120Kg and so am very concious of loading on anchors and make a point of adding an extra point in trad anchors and placing more gear while climbing to reduce the impact force. Combining climbing and engineering I spent a year analysing how the edelrid ohm (if you dont know what it is, look it up cos it your a fat bloke like me it makes a world of difference) effects loading throughout the climbing safety chain. All drop tests were done with a sand bag climber and human belayer with load cells at all key points. The cells were rated in excess of 100,000Hz with data being recorded at 10,000Hz by an external data logger. This data could then be plotted against time to see how the load was applied, how long it took to reach peak force etc etc. point being, at 10,000 Hz and being able to see the entire data track it looks as if the true peak force could have still been missed. it would be interetsing to see the tests repeated with some serious load cells and data logging equipment to see what those peak loads really were and to testing a variety of anchor set ups with 2 man loads. Another interesting point would be to see tests done on factor 2 falls onto a dyneema sling, personally i always attach myself to the master point with something dynamic. If you fancy some extra info about my work then feel free to message directly and lets see what can be done or if i can assist in any way with adding some scientific knowledge.

[@HowNOT2]

That level of research as I'm sure you know takes 10x or 100x more work and a hell of a lot more money haha. Putting out 2 episodes a week with a $0 budget gives us...... this :). I will have more Excoticas soon so every dyno is 500hz which is super good enough for what i'm doing considering my body is reading at 1 million hz :). I wouldn't wish a factor two on dyneema on anyone. I like human testing but directly attached will always be a bag of sand with a smiley face on it. I will be doing factor twos with my body with climbing ropes though! If you know of better dynos that are as convenient as rock excoticas please let me know

[@BatuYangHidup]

I have literally no idea about safely doing these tests. But could doing factor fall two test onto dyneema above some deep water be a possible safe way to do it? Anyway loving your videos. Very slowly starting to understand the more technical stuff about anchors etc from your channel. :)

[@Mrfrafrafrafrafrafra]

@@BatuYangHidup Even over water a factor 2 with a sling would be a very bad plan. As the sling would not stretch at all, your body (spine) would take almost all the force from the fall, which would be really bad for you...

[@BatuYangHidup]

@@Mrfrafrafrafrafrafra ah thanks for information mate. Better the more you know.

[@MasterEngraverTV]

I'm sure as hell wouldn't want to be the one taking a factor 2 directly onto a sling. Ouch.

[@TheManCave563]

Really sick guys, I barely have the time and crag access to climb outdoors more than once a week. I really appreciate the time you guys take to experiment with all the differnt myths and tests. Mainly so I can be more educated every time I go out and use a set up I can expect a certain amount of reliability

[@disgruntledwookie369]

Well earned subscription from me, very well thought out, safe and mature, well informed and open to new data/information. It's a pleasant surprise to see that you know at least a good amount of physics/mechanics, too many people just assume what they've been told is correct rather than taking time to understand it and even question it.

[@thizzobishi]

I've never thought of climbing in my life and I dont know how I got here but i love your content. An this video is just stunning I have no clue what any of it means but watching your dedication to science is worth it.

[@johrman04]

It would be interesting to see dynos on different trad gear placements and if shock loading affects them differently.

[@TarikVann]

Yes please.

[@mattdryden2616]

I think all of what was found here has been pretty well understood and discussed. Petzl, DMM, and many others have written about. When you read about fall factors, a factor 2 fall is considered to be pretty much theoretical since it is falling twice the length of the sling/rope with a static stop. As mentioned in this video, the human body will absorb some of that shock and if there is dynamic rope involved the shock will be further reduced. I think the big takeaway from all of it is that when you are connected directly to an anchor, at a belay or otherwise, you should aim to keep your tie-in below the anchor and keep it taught. That should avoid the vast majority of the shock loading potential.

[@christiandawson5031]

I don’t think anyone has said the first one would be an issue, rather it’s when the belayer shock loads when at the belay station. awesome video

[@ACXB24]

I'd really like to see some tests on different ice anchors and ice screws, not sure if you guys do anything like that but it'd be interesting!

[@brianrodman1033]

The ice ends up being one of the largest varrying factors making exact measurable results difficult (much more so than gear placements in rock).

[@goranlynch402]

This is an interesting and surprising result --- kudos for rigging something up and tying in for it yourself. That said, I would be strongly suspicious of a force sensor's ability to catch the peak force in an impact load while operating at 400Hz (we can skip discussion of the other sensor, since for any fast load, 40Hz is way, way too slow, as evidenced by the discrepancy in this video). I looked at the spec sheet for RockExotica sensor and it's thin on details that could be really relevant: compliance of the device itself, resonant modes, electrical filtering (antialiasing). None of that stuff would be relevant for most applications, but for detecting peak force they could make a huge difference. The data sheet's a bit cryptic but does say "Not for high speed," whatever that means. Anyway, your test is a bold one and an interesting datapoint, but without knowing just how sharp the force profile really is, a 400Hz sensor is far from a slam dunk and I would be very cautious before using this as the basis for changing anchoring behavior.

[@ohokcool]

Fully agree! Instantly thought this as an audio person since our meters work the same way. Digital meters are very limited in their ability to accurately measure peak forces due to the sample rate as you pointed out. I do agree with Ryan though that the peak forces are likely absorbed/spread out into an average force by the dynamic rope for the most part since that’s what they’re designed to do.

[@vitalii3528]

For your tests you probably can use something like 3ring release system. It basically serves as main attachment point for parachutists, and used for releasing malfunctioning parachutes in case of emergency.

[@brianrodman1033]

I really want to see some human tested daisy chain fall tests. That would be very interesting to see (or potentially frightening depending on results). If you end up doing a video on this topic I’d be happy to kick in a little cash for supplies.

[@solarmer4469]

Coming from the UK we generally avoid the sliding X when climbing and now rarely use them when highlining as well, going for an equalised overhand (climbing) or a BFK (highlining). It is really interesting stuff, but please keep safe, 4kn falls are brutal. I look forwards to seeing your tests on shockloads when a line is under tension e.g. highline/ tyrolean. It would be interesting to see if these forces would be doubled if there was two people weighting the anchor in a hanging belay situation. It would be interesting to see forces should a lead climbing take a big fall, or if there was slack in the system and your second took a fall causing one anchor to fail. Though again please don't hurt yourself! Most of the time I've thought about using a sliding X has been when I've had marginal pieces of protection, but even then subsequent 2kn loads could cause the other pieces to fail. Having seen bolts/ pieces of gear fail I usually stay clear of this. If an anchor piece was to fail and slide it could potentially drag the belayer of the ledge resulting a second fall. Thanks for you research, it really is great to see.

[@ianoco]

One trick I utilize in the film industry for FX & Stunt rigging (lots of shock loading) is adding dampers. I will tie a multiple loop of 9mm -12mm bungee (AKA Shock ) cord between two of the Shackles or carabiners in the system. For instance if I have 3' of sling/ span set/ static etc. I will cinch it to 12" with several wraps designed to allow for expansion to that final "hard" stop. This serves to "take the curse off" the stop. On dead stop ties for vehicles etc. we use tires to mitigate the shock one gear. If you do this again I would suggest adding a dangling omni or daisy chain above your tie in for you to manually hold for that extra psychological support ( with enough slack to not interfere with the test result)

[@ExtreMIX]

The stopper knots used in sliding-X type of anchor might be useful in a situation when you’re worried about potential rockfall which could easily cut on of the strands of the sliding-X anchor (so alpine climbing, when the anchor can not be placed to the side of the route line or protected by rock-feature; like a roof). It was super interesting to see the live tests on this topic 🙌🏼

[@orangeblade2]

Great to see some solid testing. Too much climbing lore is just word of mouth with no hard numbers.

[@asgymnast631]

Not sure if I missed it, but what if there's a harness failure from getting totally whacked in these videos? Didn't check to see if you guys did a test on this yet but something I was thinking about

[@comet91]

The issue I have with limiter knots is that you're compromising your first line of defense, equalization and strength of the sling, to accommodate a second line of defense of reducing shock load. I think the most important thing you want to keep is equalization since it has the greatest effect of maintaining the safety of your system. If you're having trouble maintaining equalization (e.g. top roping lots of adjacent routes), then skip the stopper knots. (although keep it redundant with the sliding x) Otherwise, use the stopper knots. Although enlightening, the problem with real-world tests is that you aren't controlling various variables involved. It's like using anecdotal evidence to rely on the infinite number of situations you may encounter. Plus, scary.

[@chavenord]

Equalization is also a myth. There is plenty of documentation about this as well.

[@ohokcool]

Shock loading might be a bigger risk than you think. Strength is not intrinsic, it can change over time and shock loading almost certainly accelerates the process of gear degradation; in that context it makes sense to compromise strength from 40kN to 20kN given that a 6kN fall is the largest fall most will encounter and anything higher than that will break your back before it breaks the sling anyway.

[@ohokcool]

The real question is what compromises the gear first: shock loading or knotting

[@mdesignz]

I think what you guys are doing is absolutely crazy! There are some shots when the camera looks down, and I can't watch! I obviously have no interest in doing what you do, but I have found your videos to be incredibly helpful regarding rigging and knots when we have to secure a line carrying a rather expensive cable cam. Thanks again for all the helpful information and truly entertaining videos! And now, I'm going to your patreon page to help contribute to what you're doing. Thanks!

[@mattm2024]

The Germans, Italians and US have tested this. In the german test I read, extension resulted in a 40% higher peak load if one leg failed BUT their numbers were inline with what you saw - ~4.3kN - It's important to look at how different belays are rigged though. In their tests, a falling climber and Belayer (belaying with an HMS from a fixed point) both had rope attaching them to the main anchor point. In other testing, where the the belay was off the harness and the belayer connected with a tether, the acceleration of the belayer downward by the falling climber (factor 2) created HUGE forces (up to 32g) capable of breaking slings. The DAV has removed all equalizing (eg extending) anchors from their instruction because of extension hazards. One should avoid tying knots in any sling if at all possible.

[@mattm2024]

www.bergundsteigen.at/file.php/archiv/2009/1/print/70-77%20%28schlingen%20und%20stand%29.pdf

[@mattm2024]

www.mountainproject.com/forum/message/111744420

[@mattm2024]

app.box.com/s/grcnlw1myjzzmta1q5gem7m5dugupprv

[@mattm2024]

www.alpenverein.de/chameleon/public/ff2266c5-af0f-8770-3b87-d84038af4cfa/Panorama-2009-2-Standplatzbau-I_18404.pdf

[@HowNOT2]

Thanks! I'll check these out!

[@benjaminjohnson4697]

Watching this one again, lmao!! He keeps asking Bobby for reasurance and all he gets is silence😂😂😂

[@aherosstory5982]

This is the most informative, yet hysterical, video I've watched ever. Fucking awesome.

[@andrewexo]

I have a personal experience with shock loading. I took a factor 2 fall onto a dyneema daisy chain that was clipped into a 0.75 ultralight camalot. There was no dynamic element - just a cam clipped into a dyneema daisy that was girth hitched to my harness. The cam held and the daisy did not break. It was painful and I ended up with a lower back injury that I can still feel a year later.

[@johntuttle9544]

That is very different than what is being tested.

[@andrewexo]

@@johntuttle9544 Yes, I experienced much higher forces because of a higher fall factor, but it was still a shock load.

[@HowNOT2]

Any footage? That isn't something I want to test because I know it will hurt? PM me at [e-mail]

[@andrewexo]

@@HowNOT2 I don't have footage. I was aid soloing when it happened.

[@johnliungman1333]

Just worth pointing out, that this is not a factor two, but something else. Fall factors are only used to describe falls with dynamic ropes. With static material, the amount of material does not matter, since it does not absorb energy. With static material, only the length of the fall matters. Having said that, it sounds scary and I hope you get better!

[@TheWtfnonamez]

"I think human testing is fun" - You "I think human testing is fun when you are doing it" - Me Good luck brother.

[@windriver2363]

I expected the forces to be less than the backbreaking 15-20kn drop tower tests we've all seen, but I didn't expect it to be that low.

[@skilllessbeast7416]

20 kN is the equivalent of 2 metric tons. The 4 kN he experienced are already quite a lot considering it is the equivalent of 400 kg.

[@user-qn9ku2fl2b]

Yeah 4kN is still a lot. thats about when harness injuries start happening AFAIK. more than this will quickly become unsafe

[@mattnorris529]

I think shock loading on cams or nuts placed on glass is a bad situation, I’m bummed you didn’t mention anything about that. If we are on two bomber bolts that are rated 20+ and our slings are 20kn+ then you’re right it is a myth. Not when it comes to ice screws or bad rocks. I’ll take a bfk over risking a hollow flake. I love your channel Ryan!!!

[@JeremyBauman-or5kc]

@13:25- yes with 2 sliding xs you have material redundancy for high forces, but not necessarily for abrasion or rockfall. A rock will snap both just as easy as one, limiter knots or a bhk consolidate the redundancy closer to the load / belay. Will this ever matter? For anyone reading, probably not. But it has happened where rock fall struck high on one leg of an anchor severing it and what saved them was that the knot adding redundancy was lower ie/ closer to the load. In their case, redundant sliding xs would have killed them.

[@heli400]

I feel like this experiment was only 1/2 done... I was expecting you to then tie a limiter knot and then fall again to compare the shock load of (with vs without), or did I miss that it was that done in another video?... yes the strength of sling is reduced with knots in it, but what forces are put on it with limiter knots in the system?

[@dragoscoco2173]

Adding knots would shorten the fall which would reduce the force with the sq root of the newfall length/old fall length. And would stiffen the sling portion of the elastic element by (2x old fall length)/(new fall length+old fall lenght). But knots might slip a bit and provide some extra comfort . Overall it looks like a 70-90% of the old fall force depending on how much dynamic rope is used. 70% for no rope and 90% for the 50 ft. My bet is on these figures.

[@HowNOT2]

If I only fell 2" it would be very very anticlimatic. Didn't think we needed to test it if these numbers were also in the safe zone. I estimate only 1kn if directly attached to a limiter knot

[@paulgush]

I'm not a climber, but a sailor and an engineer. The peak loads when you fell were greater than your weight, and the further you fell the greater they were. So, I wouldn't say that shock loads are a myth, but that you mitigate them by using an elastic rope, and gear much stronger than your static weight. That said, I'm not exactly sure what "shock łoad" implies to a climber.

[@paulgush]

Having looked up the sliding X and re watched a bit more carefully, I have to say I agree. Limiter knots in a sliding X are not a good idea

[@s9madeinchina9]

Would you repeat this experiment using cams instead of bolts? I normaly use dyneema slings with a sliding-x and never tie knots in my slings but the sudden load increase + slight change of direction have me worried that the cam might pull out... (my local crag is table mountain in SA, horizontal breaks at the stances is commonplace.) Whats your thoughts on the subject?

[@johnliungman1333]

The change of direction is not related to how you tie your anchors though, right? You would have that problem with any two-point setup.

[@trevorout]

Now I'm curious to see this type of thing done on all different types of anchor material (cord, dynaloop, rope, nylon slings, PAS). Maybe even add in some tests where the materials are wet.

[@brianrodman1033]

I really like the idea of testing the materials dry vs wet, provided it would make any difference in the results.

[@MrBobaFett]

Those numbers sure looked like they showed a shock load happening. It's a good thing you have enough safety factor to account for the shock load. (Plus a backup)

[@glennwidener3235]

Thank you so much for conducting a real-world, systems-oriented experiment and analysis of whether we should even consider anchor extension. While there are some valid minor critiques in the comments, your thrust is right on. Concerns about failures caused by extension shock loads are a myth. I rejected such concerns over a decade ago, on this basis: First, as you have shown, dropping a statically suspended climber on static failure of one placement/leg, in an anchor with an extension less than many feet long, can't generate dangerous shock forces. This is because there is always significant stretch in the system relative to the fall distance - due to harness+climber even with no dynamic rope/cordage in the system. Then, ignoring for the moment the case of cutting a non-redundant connection leg, the other primary failure mode for lead climbing is a placement failing on an initial lead fall impact. It's simple to show that in any but a contrived scenario, the total impact force on the surviving placement on extension can at most be marginally higher that the impact force of the initial failure-causing fall, and are most likely weaker. Your tests help confirm that as well. The contrived scenario which proves the rule: a short high force-factor fall, onto an anchor with long legs, low-stretch anchor connections, an unequalized connection transferring the entire impact to only one placement, and that placement being dramatically weaker, so it fails first, before the system can absorb a significant portion of the initial fall energy. The solutions to this case are long established: 1) don't use bad+far-away placements, 2) equalize, 3) don't climb above your anchor on a low-stretch personal attachment, and 3) use a Jesus nut as soon as possible on lead. Plus: build your anchors with nylon, not Dyneema! Oh, and I've been evaluating the paired-sliding-x solution to lack of redundancy, using a separate opposed biner on each sling for full redundancy at all components, and so far it looks good. There is minimal issue with extra drag at the X, even with perfectly match sliding-X's, and every reason to be believe that equalization is good (not perfect) in stretchy nylon. Your two sliding X videos are great info on how to get effective equalization, at least with dyneema. And how not to.

[@jellevm]

Shockloading is no joke and this setup seems to somehow miss the point of shockloading in my opinion. By letting one bolt fail you have tested whether one secure bolt can catch a fall (which a properly placed bolt should be able to no problem) and whether your sling survives shockloading (which it unsurprisingly can). Now in the real world, shockloading will only ever happen if that first bolt already failed! Consider the scenario there, you already pulled one bolt out (poorly placed? corroded?) and now you're relying on your only backup in a situation where you're shockloading it, putting more force on that second bolt than what made the first one already fail! What's to say the second bolt is any better? Shockloading only ever happens after you've just lost your backup. And you're now unnecessarily loading your single safety point, something which can be completely avoided, and loading it with greater forces than what made another point fail? It's unlikely that gear will fail, of course, but in most cases you at least have a backup. When shockloading becomes an issue you're likely working without any further backups, so why risk loading it when it's so easy to avoid? Why create a system where - if the scenario were to ever happen - your life now depends on a single point holding a fall without it being backed up? If you were to do that under any other circumstance people would think you have a death wish.

[@TimP569]

Very good point! I think it's easy to forget the real life circumstances for an actual shockloading scenario. If one bolt fails, it is even more important to NOT load the backup unnecessarily. As you said, there is a good chance the second bolt isn't much stronger. So thank you, I wouldn't have thought about that!

[@cleodastysm6024]

Great experiment as allways! I would be little bit scared to load the harness without dynamic element, no one says it must be the sling that breaks....

[@PB-sk9jn]

When I started climbing many years ago with traditional nylon slings (knotted, not stitched) I went into the my friends physics lab and lifted a 2 tonne optics bench that (among others) was used to develop the LIGO interferometer optics (c.f. Nobel prize for discovering gravitational waves) using a crane. That's full 20KN. More intended to test my overhand fed through than the sling. Binned the test sling, of course. Those were the days. Totally salute the idea that you test your kit guys. This shit is supposed to work. If dyneema slings were so susceptible to "shock load" there would have been a spate deaths when climbers switched. Personally, don't believe is worth giving up 44KN for. There would have been lawsuits.

[@tonygonzalez112]

Hey Ryan what do you guys think about using ballistics gel to imitate the human body for actual forces. I think it would act more like an actual situation. Just a thought. Your vids are great.

[@davidwarren719]

Ballistics gel is really bad at imitating organic tissue-not the goal of it. And it can be tricky to handle, because depending on the formula you use it may melt at low temperatures.

[@chamonix4658]

Ryan you are amazing! Glad your at 100k subscibers now, well deserved!

[@tonyanderson8053]

I loved this video. I have been using two slings (for redundancy) in a sliding X as anchors for decades. I am a loads and dynamics engineer in the aerospace industry and the idea of "shock loads" in a system that has a lot of compliance like a dynamic rope just does not make sense. The knots in the slings do more harm than good, which you have shown in other videos. You even took the rope out of the system and didn't see real high loads. A comment on your instrumentation: you need to look at the plots of the data and see if you are missing the peak load. The 40 samples/sec is probably missing the peak by quite a bit and the 500 samples/sec is probably capturing the peak pretty close, but you don't know unless you check.

[@Ilbriccodellorsosat]

Hey! Great video! I've got a question: do you think the fact that you're holding to the rope above the dynamometer during falls affected results? Thanksss keep up the good work!!!

[@HowNOT2]

I can't do a 1 arm pull up at all, and i couldn't do it with my hand at my face. I could be taking 20lbs off maybe?

[@jonflannery8984]

Sliding X times 2 gets my vote. Thanks for the awesome content man.

[@vladimirmolodojen5110]

Nice test, but it's shows that shock load is real, not a myth. Your weight is 0.8 kN approximately, it was loaded on master point - and there was on master point 4,44 kN in the worst case in your test, more then 5 times more! It is the most important - because in other test the shock load was absorb by dynamic rope. So, if I will belay my partner througth the master point, and he will fall down with FF about 2 - instead of 0,8 kN, after absorbing by dynamic rope, it will be about 8 kN on climber (max impact force for modern ropes) - and it means about 13,6 kN (8*1,7) on the master point. If in such situation one of anchor points will break - by your test, it will be impossible high force on the master point. Multiplication in your test is from 2,5 till 5,5 - so, after breaking anchor point on MagicX it will much more then 22 kN - and dyneema will be break too. Finally, especially for trad anchor, we have to think abou shock load a lot, and your test it is good demonstration of it.

[@REVOLUTIONS51]

Yay! I was looking for someone to point out that the problem may come from the climber falling on the belay in the next pitch! That's where you'll see the high forces you do not want to moltiply for no reason, even though we still have a dynamic rope in the system. But we would have a person belaying you, it's a complicated scenario....

[@TheScottttttt]

I think you would need to test to see if the shock loading causes a multiplicitive effect on a factor 2 fall with a dynamic rope in the system, and to what extent. It seems unlikely that in reality you just take all the numbers from the very different experiments and multiply them together.

[@vladimirmolodojen5110]

@@REVOLUTIONS51 exactly, it is more complicated scenario - with much more significant forces. By this reason imho it is not correct to recommend forget about shock loading after test on video - because test shows significance multiplication effect.

[@REVOLUTIONS51]

@@TheScottttttt well a factor 2 is already 7 kn on a grigri (with most ropes), if it's a "dynamic" belay it may go down a bit but remember, on the master point you'll have both the force to the climber plus the force to the belayer, so above 10 kn for shure, so it's not necessary to multiply that much. And that's the reason I go with a 7 mm kevlar accessory chord instead of dynema as it does not loose as much strength when you tie it.

[@johntuttle9544]

The point of the video is that the additional distance caused by a sling breaking at the anchor is insignificant in a real world scenario. If your anchor is so bad these tiny additional loads would matter then you have got problems with your anchor, not with "shock loading".

[@cornishlad97]

I will add tho ive been watching your channel for a fair while now and its incredible to see someone put their money and life where their mouth is and really test there logic. i dont dispute the reasonable accuracy of the static testing on the slacksnap machine and with cells in your highline anchors, space nets etc but the dynamic stuff could likely use a little more thought

[@HowNOT2]

I've learned how NOT to break my exoticas now! Plus I have more. But I don't know of any other devices that are handy enough for me to take in this context to get better results.

[@cornishlad97]

@@HowNOT2 deffinetly right about handy. The super accurate kit is far from handy. In fact it has to wired to a PC to data log anything!

[@MrRaandom]

I'm thinking - what if the first bolt blows at the point in a fall when rope already is stretched out and the human body already has absorbed quite a lot of energy? My point is - the safety factors such as friction, rope stretch etc might already be engaged and not available when a bolt fails in a real life fall because the event that caused the bolt to fail might already have used up some energy absorption. You'd possibly see higher force readings then. That said, I love the video, thanks, keep up the good work!

[@HowNOT2]

Add 4 more kn to the rope, and it stretches a lot more. A rope is never done stretching.... until it SNAPS! haha

[@BigToinE976]

At the moment where the bolt break, there is no force applied by the other anchor to the main anchor's biner because the biner in the sling has to travel from the middle of the sling to the end of the sling. So at this moment, the rope and the body may relax and prepare for the next shock ...

[@eugenejkim]

👏👏👏 kudos for doing the experiment yourself I'd rather put limiter knots in my slings if I'm using cams because 17-19 kn > 14 kn my cams are gonna break at. 2 slings for 2 sliding X's tho 🤔...

[@HowNOT2]

True! Keep in mind the cams are seeing only half the load. If the master point sees 14 or 19kn for brand brand new then each piece is only seeing 10kn and your sling would break first. Just don't get 14kn! :)

[@eugenejkim]

@@HowNOT2 good point!

[@q35h70]

What is that big black thing in the lower left of your pegboard?

[@tylerdraper3291]

I'm so happy I'm not the only one who saw that 😂

[@bt5294]

Did you test the two sling sliding X or make a video about it?

[@audiomystic]

As an electrical engineer. Seconding what another engineer said here. You must analyze the ‘speed’ of forces in the system. You would want to know how much ‘dampening my there is in the system and understand what time constant the forces occur in. 400 Hz reading is very very slow. For example, I prefer measurement at 192 kHz for audio rate dynamics of amplifiers, but even 10 MHz sample rate reveals even higher peaks. Under sampling, you are relying on luck if the peaks align with your slow sample points.

[@andrewmclean6721]

Fun video and very informative. Forgive me if this point has been raised but ropes and slings can be cut by rock fall or ice tools or static hardwear etc. A sliding x will then fail completely. Redundancy doesnt just cover anchor failure. This is well covered in Accidents in North American Climbing with real world examples. As to your question on limiter knots v none, the strength decrease seems offset by the shock absorption so I would favour some limiter system. Really addicted to your site. Cheeeeeeeaaaaaars

[@winterroadspokenword4681]

The one thought I had was before trying something you don’t understand make sure you’ve got redundancy. I know the loads are low, if you’re only wearing one harness. If shockloading that is bad in some way, you’re gonna have a fun trip to the bottom😅 I would definitely have a backup harness on before testing things in a way you’re not supposed to!

[@joshuafryer3370]

Awesome videos! I would love to see you guys test the debate on using a grigri for trad vs an ATC. Concern is added stress to protection in the event of a fall. Is using a non-abd device worth it? Also JUNO COFFEE IS AMAZING. Get some, it’s my go to outdoor coffee, plus in the office at times.

[@windriver2363]

Besides shock loads, or the lack thereof, something to consider is that the extension of anchor master point may lead to a difficult or even dangerous belay situation. You may have difficulty reaching back up to the anchor, or it could affect your ability to belay. There are many potential complications it could cause.

[@pentachronic]

Hence the reason these guys know about self-rescue, prusiks and ascending ropes along with using alternate anchors or climbing lines.

[@masonluedke9712]

Every time ryan said 'this is scary' I was thinking that they could just use a haul bag instead of a human for testing

[@HowNOT2]

But would you watch it as closely??? ;)

[@largeformatlandscape]

@@HowNOT2 Plus the human body interacting is a major component in a real world test!!

[@juliencarraccino6202]

Hi, thanks for all this Amazing job. About building an anchor with 2 dyneema sling sliding x serms intersting for redondancy but if a rocks fall it may cut the 2 slings because they will be AT the same place, too close from each other and you kind of lose the redondancy i think. What do you think ?

[@Chris3141592]

I like this channel and your videos. As I work in a vertical realm the videos are also helpful in that regard. My question is this: is the video footage admissable as "professional" expert subject matter reference or is it anecdotal amateur reportage?

[@HowNOT2]

Its a guy with a Iphone 11, friends and way too much gear. Who cares if i'm legit or not - people can take the information and consider the pros and cons of the experiment, research other people's tests and make decisions on their own. We do try to make our stuff better with each episode, but with a budget of 0 and 2 episodes a week, I can't get too fancy. Plus I try to appeal to a broader audience than just gear nerds who love charts. haha

[@chrismoon1584]

You should care dude. This information can kill people if misinterpreted. Challenging safety is reckless af. You can make whatever argument you want but at the end of the day.. it's bad for the safety of your community. Trying to understand how you can soapbox about safety when you are publishing videos that make it seem like it's ok to disregard best practices.

[@largeformatlandscape]

Chris Moon if you take advice from a KZbin video which is warning you not to take it as advice and base your life and safety on it then perhaps you were Donna die anyway. I for one like to have this added real world understand of the moderating effect of a human body in a system and I can draw some useful conclusions from it. I’d be less certain about an industry recommendation without visible test evidence to support it. Don’t forget, the industry has got it lethally wrong many times in the past

[@JeffAVideo]

Is that a Master Series X-Large Spades Beads rack on your wall? Would you call that Bomber as a meat anchor?

[@DavidBairdSailing]

The Eiger Sanction reboot is wild.

[@olegx.8173]

I suppose the idea beyond limiter knots on climbing anchor sling is that it would be shock loaded if the leader falls, not the second. Fall factor even in the last fall was well below 1. So it would be much more useful to test a possible leader fall on sliding X scenario, although I doubt it can be human tested in a safe manner.

[@partybowl69]

I love you and your nerd wisdom about exploding capillaries :)

[@davidi1213]

Another great video. Can I suggest another test? I'm into LRS and one suggestion for a ground anchor using the first 2 bolts on a sport route is 8 mm maillon and fig 8 onto bolt 1 and rope running through a 6 mm maillon on bolt 2. The idea is if bolt 1 fails the 8 mm maillon and fig 8 will jam into 6mm maillon on bolt 2. Any chance of testing this? Thanks guy from the UK. The via are useful but also funny as hell.

[@cooperspace90]

Really exiting testing, looking forward where this leads! Thanks!

[@davidwarren719]

I don’t know if that was a subtle pun, or a really unfortunate typo 😂

[@cooperspace90]

@@davidwarren719 reading it again, I am... undesided

[@JeffMeadowsOutdoors]

Not directly related but similar, Have you considered testing the forces from falling on via-ferrata? I would love to try those out.

[@lolaa2200]

for few years now i ditched the dynema webbing for anchor and use pieces of thin dynamic rope so no need to fear about shocks anymore. I think that's the recommended thing for anchors from international guides agencies nowadays. So what i use is 2m pieces of beal opera ropes that are thin but still rated for single roping. Just my 2cts...

[@Zeric1]

UHMWPE should be avoided in anchors, that has been known for a very long time. Not only due to shock loading, but more importantly in trad anchors is equalization. Nylon does much better at equalizing it self due to it's inherent stretch. Anchors inherently require knots in the material which significantly weakens UHMWPE. UHMWPE is meant for sewn trad draws where there is a lot of rope out in the system, it is not meant to connect multiple anchor points together and utilize knots.

[@xxanimexnerdxxkelson]

That story was about Colonel Stapp, who was testing acceleration and deceleration forces on the human body during high speed flight

[@justinzaff]

I admire your courage for doing that test yourself 💪

[@clarkeysam]

I'm not even a climber but I enjoy your experiments.

[@CDW98]

“and all his capillaries exploded and his retinas almost fell out..... that’d be pretty funny if that happened from this”

[@carlosrezende8277]

A curiosity, what kind of carabiner or system did you use to loosen the anchorage and cause the fall?

[@TheArmyKnifeNut]

For me, limiter knots are not about reducing the shock load... its all about redundancy. The difference between 6 inches worth of shock load vs 24 inches of shock loading isn't likely to be a big deal compared to the strength of the gear (especially with any dynamicrope in the system), but if abrasion or rock fall results in one of the strands failing, a sliding-x equals death, while a sliding-x with limiter knots, a quad, a BFK, etc will all still keep you alive. I appreciate your idea to use two slings for redundancy, but a doubled up sliding-x could still fail in situations where a knotted anchor won't (ex: rock fall severing one side of the anchor). Final thought is that even with the strength loss from the knots, the strength is still stronger by a factor of 1.5-3 when compared to 1. the forces generated in a fall (a long lead fall might reach 5 kN max), 2. the forces a rope can endure (ropes fail way lower than anchors), 3. the forces trad gear is rated to hold (most gear will fail long before the knot rips), and 4. the forces that would seriously injury or kill a human (44 kN on your harness would cause the harness to fail, or rip a person in two). So, for all those reasons, I'll take redundancy over overkill strength any day.

[@HowNOT2]

I agree with your thought processes. If I build a highline anchor, I'll use two or three slings and do a sliding x because I want highest strength possible. If I set up a top rope anchor, I'll just use two slings and do a sliding X. The limiter knots, if pulled hard enough break in the knot and is NOT redundant. But it is if something cuts a strand but then the dyneema slips eventually. This works better in accessory cord or even nylon slings. Ropes will break around 15kn and so will your belay loop but if in a top rope scenario you will get not double but close to it so it's nice when the anchor is a bit stronger than the potential of the rope. A little shockload in some situations is not the end of the world. Ideally it doesn't happen at all but I like to explore these die hard rules taught to use in climbing. Cheers!

[@nightloader2]

I like using a sliding x with a 60cm runner to get the benefits of a stronger sling, distributed weight, ease of untieing after load, but a short distance if shock loaded. I'll use other slings to reach the point where the short x is. Then I back it up with something else, often using the rope directly into additional pieces of pro if a gear climb, or in series back to the bolt anchor.

[@horaciovinuesa]

I don't think there's a way a human can fall and break a dynema sling (with no indications of being too messed up... jeez, even with the sling a bit messed up there's no way). Love to see these tests to confirm that a quad made out of a dynema will hold more than 20x the neccessary for single or multi pitch. Thanks for the tests, you guys are the best.

[@johnmallette3143]

ahhhh! this might be stupid question,.,.when you climb do you leave your anchors behind ,.,.how do you recover them or does the guy behind take them as he passes them.,,..idk how to ask really.,,.??

[@HowNOT2]

In multi pitch climbing the second climber takes all their personal anchor equipment with them when they leave the anchor.

[@richardsmith9918]

😁 wow I haven't felt felt comfortable with getting off the 7 ft anchor yet. I like to climb upto it since it's a column of mortared granite and drop in from the side to recreate the 18ft one. Think I'll use a personal anchor to get out there then set up my atc

[@ratherbyexploring4898]

The industry should stop believing that limiter knots in a double length sling is a redundant anchor. The slack snap video showed that the sling consistently breaks at the overhand knot and then the overhand rolls off the broken end resulting in the masterpoint falling off. Not redundant! You should trust the multiple sling anchor and if needed clove one of the slings short at the piece in the case of a slack on a sling (indirect pull)

[@TheArmyKnifeNut]

Limiter knots are not about redundancy when it comes to strength. If you're experiencing forces in excess of 15kN at your anchor, something has gone horribly wrong. The redundancy from knots is redundancy against accidental failures of the cord or sling. If you have a sliding-x made from a sling with a worn and weakened point, and that tore, you're screwed because your entire anchor will fall apart. Put in a limiter knot on either side of the master point and you would survive the same failure. If your defense to that scenario is "I always inspect and retire my equipment when it shows signs of significant wear," what about rock fall? A sharp 30 pound block is dislodged by your climber above and it slashes through one of the legs of your anchor. In the case of a sliding-x, you're dead, but limiter knots on either side of the master point mean that you'll shockload the anchor, but if the gear that the other leg is attached to is good, you'll live, and even in that scenario, you won't come anywhere close to the breaking strength of the knotted sling. Bottom line: Redundancy against abrasion, wear, or accidents like rock fall is more important than multiplying the safety factor from 1.5×-3× up to 3×-6×. That is overkill.

[@Zeric1]

Limiter knots should not be put in UHMWPE material. I prefer nylon for building anchors anyway as it has much better shock absorbing properties, but if you are going to use UHMWPE, don't knot it as it looses far more strength than knotted nylon.

[@slowgold20]

"Augh! I hate lab tests!" ... "Is there any way to make this safer?" yea lol, build a better lab test

[@HowNOT2]

its a hard balance haha

[@slowgold20]

@@HowNOT2 no joke though, I really appreciate you doing this because no matter what real life is different then a lab. So thank you!

[@manuelsidler]

I'd love to see some daisy chain break tests in these scenarios. I'm always told how dangerous they are outside of their aid climbing design but I still use them on occasion as my PAS, how dangerous is it really?

[@brianrodman1033]

I just left a similar comment about wanting to see daisy chain fall tests. When aid climbing/big wall climbing nearly 100% of the time I’m clipped in with a daisy chain as my first personal anchor (and always backed up though) whether at the belay, leading, or jumaring to clean a pitch. It would be great to get some information on just how careful I should be when attached with a daisy chain.

[@phutton88]

Go Bobby Hutton!

[@Papershields001]

I think I might just put two sliding x slings in now rather than limiting knots. I’m sold.

[@chrismuntean]

My friend told me a story about one of his friends that was ascending a top rope at the gym to set a route. I think he was using one of the more original triangle shaped Petzl belay devises and he tied backup knots as he was ascending. The grigri failed and he didn’t tie a backup knot recent to when he fell and ended up falling 10-15 feet or so. Everything held fine but I think he broke his back, but he for sure had tons of back pain after the fall. This was on a (probably old) dynamic rope.

[@kap8495]

yay more climbing stuff thanks guys love your work :)

[@shanalucille]

Wow, cool. Highly education and entertaining. Thank you!

[@cmd2023]

You guys did a great test video.

[@questionablebutconfident3]

dude thankyou for putting in your efforts towards everything gravity related, truly appreciated across the globe, you rock man!

[@thepoetato6201]

I'd like to make a case for the limiter knot. While I now agree that they aren't that important for preventing extension. I would argue that they are worth using still, because could make the anchor more redundant. Of course, you can use the method you described in the video of doubling up on slings to be redundant, however, there is a real life scenario where that wouldn't be as useful. The scenario I have in mind is rock fall. During a rockfall, the sling could be cut and cause a total failure. Using limiter knots, you would reduce the length of sling that is exposed to that possibility, and you could survive with a single bolt connection remaining intact after the rockfall if a cut were to happen on the outsides of the limiters.

[@HowNOT2]

It is redundant from abrasion or something cutting it, but not if it breaks in knot, the entire thing unravels.

[@CanyoneeringUSA]

Super awesome. Your best test ever! Sure would be great dropping a block of steel in the same manner, to pseudo-calibrate human vs. steel block.

[@CanyoneeringUSA]

Coffee purchase made. Thanks.

[@mutfriedhartmann2205]

If the bolts are week it could be better do save the bolt not the sling. In this case it could be a good idea to avoid the shock load.

[@rockclimbinghacks9222]

This test doesn't address the climber's concern, which is a factor 2 fall on the anchor. Here's what you could do to test that: -build an anchor, left leg w/ load cell, right leg connection built to support only bodyweight. -have belayer hanging from anchor catch falling climber mass (you can test this with belay off harness vs belay off anchor) -compare this with a non-extending rig like the overhand loop (still rigged with the right bolt to fail on catch, load cell on left leg) Failing bolts/pieces do not absorb energy as I recall, so this should be a pretty good test.

[@iacamigevaerd376]

Hey, I've been seeing more and more people using accessory cords for building anchors, most common one the quad. People use some technora or kevlar usually, but some even use regular nylon cord. I'm curious about the mbf for these when knotted with 4 strands (the quad). Cheers

[@lorenzodalsanto9831]

thanks for the informations! if I can give you a tip for a video, it would be interesting to see how lead rope solo falls load the anchor and the last protection clipped

[@skethoo]

there is nothing stopping you from sliding out of sliding X if the sling is cut during the accident.

[@joffyjenkins9241]

At 12:20 he makes that point, then at 13:00 he moves on to how he could make it redundant due to this.

[@TheArmyKnifeNut]

@@joffyjenkins9241 Except that second idea still isn't redundant against something like a rock fall landing across one of the legs of the anchor and cutting through the leg... limited anchors are still superior in my book and my go to anchor for sport is a quad made out of cord while my go to for trad is either a limited sliding-x or a roughly equalized overhand or figure 8 made from slings.

[@HowNOT2]

Use 2! or 3! or quads! Quad testing coming in next few weeks!

[@mijodo2008]

This testing routine has a Sphincter Factor of 12 out of 10. 🤣. Cheers from Michael. Australia.

[@Candesce]

I feel like the weakest point in a shock loaded system is the belay loop, so I would be very concerned if your belay loop was your single point of failure in a shock loaded setup.

[@mikeyvon23]

Does anyone know of a video that tests if using detergents on climbing ropes really weakens them? If not this guy should do a video on that!

[@BatmanProject777]

Not a video, but I've read articles about tests with different chemicals....including gasoline, kerosene, etc. From what i recall, nothing hurt it except acid.

[@admad1958]

There is an Edelrid video on you tube where they show the effects of contamination with acids and bases (most detergents are) are very serious on Polyamida.

[@RadagastTheBrwn]

this dude is the linus of the outdoors

[@MaxLiubashenko]

What an interesting idea of using two similar slings for sliding X! But I believe it won't increase redundancy near as much as a pair of knots on the sling. If some flying rock (or friction on the edge etc) will hit your anchor it will cut even the doubled sling.

[@HowNOT2]

"flying rock" has been brought up quite a bit. I'd love some real life stories of flying rocks that we work hard to protect ourselves from. If a rock is big enough to cut through 1 or especially 2 pieces, it's big enough to do some serious damage to you while you are attached to it. I'll see if i can get some flying rock stories from the audience

[@markweedon5678]

So Ryan, why are you making your anchor doubled, see redundant, if not to protect yourself from death if one sling was to break? What would break a single sling strand that would not break the double used with two slings? I think I'm probably still going to add two knots, if not, just for full redundancy of all anchor points. The one thing I might take from this could be the use of Nylon with limiting knots. Thanks for the video btw. Has got me thinking about this a bit more. Appreciate the work, time and effort put into it.

[@marcsyrene3781]

A friend of a friend died while rappelling in the Winds from a rock cutting multiple slings wrapped around a rock at a rap station. Very sad indeed. Which, brings up the no bolting in wilderness area debate. Bolts at anchors seems reasonable to me if hand drilled. A lot less garbage to look at too.

[@ReadySetGoPictures]

2:18 - are you rappelling on a single line using a gri-gri? I thought this wasn’t recommended? Or am I wrong?

[@HowNOT2]

How is it different than lowering a climber?

[@ReadySetGoPictures]

@@HowNOT2 My thoughts exactly. I see its "Not recommended" but it seems like the exact same functionality to me. I don't know why its not recommended, or if thats just a using legal saying so they deny liability if something bad happened.