Lead falls in climbing gyms - how much forces does it generate? Climbing Science! 

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The ropes are durable and just like the ones at the gym. ru-vid.comUgkxTFxba6lNeHrZaHoY_LXe6ZzmMfaipnwu Caution: I bought the 50 feet ropes and they are long and heavy so make sure you have the space (I do have the space). If I was to do it again I would probably get a shorter version as 50 feet (25 feet each side) is a little long.

I would love to have seen more "small falls" - The math of the fall factor favors bigger falls because there's more rope. But what about falls on the first bolt, or falling past the belayer? Factor 1, 1.5, and even 2 (though don't do with with people!)

Different belay devices would be really interesting. There's a lot of slip belaying with an atc, but I'd be curious to see a gri, smart, jul, etc.

Really well made. Could watch this all day. Looking forward to the following ones.

Ryan, as a ~330lb climber I would be very glad to see some experiments with somebody my size. My gear fear continues because seeing tests with people that weigh half of what I do doesn't fill me with confidence that I can ever lead climb safely.

There is a very well presented grabbing instinct by the falling leader which additionally lowers the reading on his dm because he happens to grab above it. Worth pointing out.

Watching this makes me feel so much better climbing outside. It turns out that it's pretty hard to generate an amount of kilonewtons that threatens even basic gear's tolerance. Good to know!

Climbers weight in "lbls", forces in "Kn" that are direct translated to kilograms... Please help the rest of the world.

I weigh 245 lbs, I’d love to see what kind of forces my weight places on the gear! It’d be real cool to see if it’s graphable on scale with weight/height of fall. I also climb with an Edelrid ohm, because most belayers weigh less than me. Have you thought about testing these out to see what kind of load/force reduction they actually make for the belayer?

Thanks for the video guy's. I would have liked to see a slightly larger climber, maybe 200lb's or 90kg. I would have also like to see double ropes put to the test and some trad protection, nuts rather than cams. I really appreciate what you have done so far and keep up the good work.

I feel like there aren't any good videos explaining fall factors, and that type of content would suit this channel really well. I bet you could make a video MUCH better than what's out there right now.

No experience in Climbing, climbed once in highschool when i was a kid, never slacklined, still watching your videos anyway, for the science, and the logistics insight !!

Looking forward to high fall factors. Would _really_ love to see force vs. time plots.

I would like to see a video for solo rope techniques, such as anchoring off the first bolt.

I'd like to see a test of a leader fall that zippers out a few questionable pieces of protection. do the first couple of pieces take enough of the force to allow the 3rd piece to hold the fall? Also, how good does an Ice screw placement need to be to catch a screamer?

Do one showing the strength of guide ATCs? I cant seem to find ratings on them however they are made to be clipped in directly and take the same force the carabiners would normally take it seems? But they don't how a rating on them.

Hey! Would you maybe test some Chinese Carabiners from eBay or something? I would be really interested in if they are as good as the branded ones... cheers!

I'd love to see some tests comparing the forces generated in a fall when belaying directly on the anchor vs belaying over your body at the anchor.

smaller cams are supposed to hold 5kN so it would be cool to see some experiments on rock on how much they actually hold

For the question why the forces don't add up I was instructed that the friction in the draws and the elasticity of the dynamic rope help absorb part of the energy. As for suggestions. I've plotted all the data you provided, including climber and belayer weight, and did not find any correlation to the results. I think there are more variables than considerate. Some things I would do trying to get more consistent data: 1- Have the climber fall when the knot on the harness gets to a reference point, this would mitigate any problems on having more or less rope on the system depending on the climber height. 2- Have the belayer positioned always on the same spot, same justification as above but now considering his position toward the wall. 3- Guarantee that the belayer has a standard slack/no-slack amount of rope on the break. Same as the two above. 4- Measure how much rope is the the system from the break till the climber. Having the estimated fall factor might help understand the trends. 5- Have more than one fall for each test, average or deviate the numbers so there is more consistency to the results. 6- Have tests where the climber is lighter than the belayer. This situation is very common and might look more a static fall 7- Try different setups with less or more draws in between. You can never have too much data lol 8- Rope technical information. We can add the elongation on the math and try to determine the influence on the rope on the system. I think that with this much information we can try to determine between fall distance or weight difference which contributes more to increase the load, as well as any correlation with the fall factor and how much impact does having more or less draws has the in the system. I weight 211, and always feared that when I fall I was pushing more KN than that. Is good to know that I can still add more load on the rope before snapping it. Like I said before, what you are doing here is extremely helpful to the community, if I can help on any way just let me know.

How about higher fall factor?

Great video, love what y'all are doing!!! I would love to see some tests on factor 2 falls. Very applicable to the climbing community, and I'm sure it would pull in more viewers. Thank you Ryan and team!!!

This was awesome. More please! As to why they don't add up, - work done by friction - difference in catching "softness" - amount of rope to increase the time in the equation of (Force × distance)/time there by decreasing the amount of dynamic peak loading

I have always wished to see how poorly placed nuts and smaller sizes with 3-point contact hold up. Like, how well can a DMM Peenut semi-well placed hold?

Would it be possible to enhance the dynamic properties of dyneema using some sort of screamer approach? Possibly some kind of mechanical solution?

Well done!!! Keep going. Please, use international units. Congrats.

What ropes were used? The specs of the ropes would make some difference I would suspect. Ex. Beal vs Mammut, stretchy vs less stretchy.

Can anyone tell me whether a 22kN MBS line is good enough for a highline setup? 7% elongation

This makes me feel so much better as a rope tech that my gear is designed to take over 8x times the shock loading of the hardest fall here. The force required to actually break my gear is equivalent to forces that would literally shatter all of the bones in my body lol.

any chance you'll do the same experiment on trad gear?

Come test on me. I'm 270 and lead climb 5.11.

You should add a dynamometers to each quickdraw. Them are acting like little belayers. That is why you miss some forces at the belayer but more or less you have 2*climber at the bolt. Interesting to note that from 1.5 to 7 (in the Z) times of the climber force is absorbed by the quickdraws.

I'd love to see a dynamometer on a cam(of different sizes) catch a whip outside (backed up with a bolt below) and see what kind of forces it has. Curious if they're less or more than the bolts in a gym.

Here are the force distribution ratios, for those who may be interested. (code included) - 76kg (167slbs) Short: climber/belayer: 2.6 bolt/climber: 1.7 climber/belayer: 2.5 ---- - 76kg (167slbs) Long: climber/belayer: 2.2 bolt/climber: 2.0 climber/belayer: 2.25 ---- - 79kg (175lbs) Short: climber/belayer: 1.8 bolt/climber: 2.3 climber/belayer: 1.8 ---- - 72kg (160lbs) Z drag: climber/belayer: 6.8 bolt/climber: 2.0 climber/belayer: 6.8 ---- - 79kg (175lbs) Long: climber/belayer: 1.8 bolt/climber: 2.0 climber/belayer: 1.8 ---- - 86.1kg (190lbs) Long: climber/belayer: 3.0 bolt/climber: 1.7 climber/belayer: 3.0 ----750750 - 76kg (167slbs) Static: climber/belayer: 2.3 bolt/climber: 1.7 climber/belayer: 2.3750 ---- - 72kg (160lbs) Big: climber/belayer: 2.2 bolt/climber: 1.4 climber/belayer: 2.2 ----750 The estimated 86.1kg (190lbs) Long belayer used for the calculation: 78.116 Code: onlinegdb.com/rka4IRA7L

Microtraxion and tblocks on ropes!!

Wait, you call your instrument "dynamometers", but a dyno measures POWER and your instrument measures force? en.wikipedia.org/wiki/Dynamometer

Need more of this available to the community

Some work is done on the rope to stretch the rope itself, so the rope essentially distributes the forces throughout. There is still conservation of energy but some of it is lost between the measuring devices to the rope itself, which is why the belay/climber readings dont sum to the bolt.

Hey Ryan, we'd love to see more tests with climbing gear here are some ideas from my end: - Edelrid MegaJul how much is needed to break this device? it look weak (and is cheap in testing because it not expensive) - Quickdraws: my (online)research showed that most of them are barely over the mbs - Friction until burn is this possible? e.g. a 100m rope with e.g. 100kg and high friction on the belay device (e.g. tube) use 99m and stay on the last meter, is it so hot that it burns trough? - zig-zag belaying in case the belayer weight is much less than the climbers weight: what could go wrong?

I am guessing that the bolt never experienced the full climber and belayer due to rope stretch and friction from the other quick draws?

The reason Bolt does NOT equal climber + belayer. The belayer and the climber both pull down on the bolt/pulley with their indicated forces. However friction with the "pulley" causes the pulley to pull up on the rope (and thus the rope to pull down on the pulley, Newton's 3rd law of motion). It is the frictional force that causes the discrepancy between the force on the belayer and climber. The amount of the friction must therefore be equal to the difference between the pull on one end of the rope and the other (discrepancy). The total down force on the rope is equal to the sum of the climber and belayer, plus the pull created by friction. Climber force minus belayer force = friction Friction + climber+belayer = total downward force on pulley. Here is one example from your data. (1.78 - .99 = .79 friction) climber + belayer + friction = total .79 + 1.78 + .99 = 3.56 theoretical total (actual measure total was 3.54) FYI: you can also get the calculated total simply by doubling the climber's fall force. 1.78 * 2 = 3.56 FYI: using a low friction pulley would decrease the difference between the belayer and climber, but the formula would still work. In the absence of friction the belayer and climber would be equal, and their sum would equal the bolt. However, you would never be able to have a 100% efficient pulley due to the internal friction of the fibers as the rope stretches and bends. FYI: I am a high school physics teacher, and hobby climber (top rope and TRS only).

Pretty sure the answer is friction. As a thought experiment, if you whipped on a magical frictionless pulley instead of a carabiner, I think the tension in the rope would be more-or-less the same everywhere. So the climber and belayer would experience the same force, and the pulley would experience up to 2x the force depending on the angle. Unlike a magic pulley, carabiners act as a capstan and cause a lot of friction against the rope. The friction force acts on the belayer's side of the rope, which is why the force on the belayer is always much lower than on the climber. But the friction force on the rope has an equal and opposite friction force on the carabiner (Newton's third law), so you _still_ see up to 2x the force on the carabiner. In theory anyway! In real life I'm sure it's way more complicated =D

Would love to see same tests done with DMM revolver. There was a big math argument years ago among mechanical engineers and I’ve wanted do this test forever. The question being, using a revolver would lower or raise the force seen on an ice screw or crappy trad Cam placement? It looks pretty clear though that: Higher friction in the rope *after* the top carabiner = higher force. What about @ the carabiner? Seriously. I’ll doordash beer to Sacramento for you guys doing the test. (With enough notice I might even drive up and bring the beer myself!) HMU.

I tried using pully lockers on my sport anchor master point. Without the friction I'd yank smaller belayers up the wall. They seemed like very soft catches though. I wonder how the loads would be different.

I'm just getting into ice climbing. The biggest issue for me though, is I'm currently 275lbs. The math is NOT in my favor.

Please add units to the table

Why is belayer KN + climber KN < bolt KN? Belayer and climber both enjoy the benefit of rope stretch and friction while the bolt does not. Note that in general, twice the force at the climber is close to the force at the bolt Mel's Long fall climber force 1.78 x 2 = 3.56; force at bolt 3.54, a difference of 0.02KN, greater on climber side Mel' Small fall climber 1.26 x 2 = 2.52; bolt 2.88, difference 0.36, smaller on climber side TJ small climber 2.14 x 2 = 4.28; bolt 3.72, difference 0.56, greater on climber side TJ long 1.73 x 2 = 3.46; bolt 3.46, difference 0.0 TJ static 2.65 x 2 = 5.30; bolt 4.52, difference 0.78, greater on climber side Mel + vest 2.34 x 2 = 4.68; bolt 4.06, difference 0.62, greater on climber side Ryan Z drag 2.43 x 2 = 4.86, bolt 4.78, difference 0.08, greater on climber side Ryan K big 1.87 x 2 = 3.74; bolt 2.6, difference 1.14, greater on climber side

Using TJs static test as my example 2.65+1.15=3.8 20m of rope out with 37% stretch = 27.4 5m fall 5/27.4=0.18248 (3.8*0.18248)+3.8=4.493 Given these are all estimated from a video (but the math is close)

This is awesome! Exactly what i needed to see! I did some mathematical simulations in the past to see how this all worked. But was never shure about the actual forces due to friction (especially all quickdraws combined) and rope elasticity due to ciclic loading. It changes over time and after heavy falls, rope needs time to reset. The equalization and highline anker video's were enlightning as well, though the forces are applied in a swelling manner, instead of an abrupt way. This will most definetly have some effects. Ideas: - Film with a thermal camera. (Here in the netherlands we can rent them.) This could visualize the heat very intuetively. (quickdraws, belaydevice and rope!) Request: - Using these measurement devices in a climing anker. (i know, the lines are to short for that, but i've seen you being creative before! ;) ) - Dropping a load of a (WAY TO HIGH) location. Perhaps using some old discarded climbingropes to see where they would break. The knots or the anker setup. Notes: - If you need any help with calculations, I might be able to help ;) THANKS!

Basically, though somewhat helpful, without plotting the graph for fall factor, this test fails to shed light on fall factors between 0.5 and 2 (the critical range). Testing the actual limits would be forever helpful to the climbing community.

The space between bolts in some routes here in EU is sometimes 5+ meters (16 ft). Would love to see a 10+ meter (33 ft) whipper.

Would be interesting to see soft catch compared to hard catch to see how you can reduce the force on marginal gear placements

Im guessing that Climber force + Belayer force + Friction Between Belayer and Bolt force = Bolt force. To prove it you would need to do a drop in the first bolt, that way there´s no friction between Belayer and bolt and now the climber and belayer force should add up to the bolt force.

Hi, I wolud love to know much kn stress does hte Beal Dynaloop reduce in the anchor compared with an static system such as a dineema quad. I mean... Lets take the firts example of this video (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-fZIj5HAV8xA.html) and say with a dineema the anchor is 3.21 KN the belayer 1.08 KN and the climber 1.92 KN. Are the forces recuded by a lot or is it like nothing? Congrats for your amazing videos!

I'd like to see this same experiment with the Elderid Ohm incorporated with its own meter to see how much force it really does eliminate from the rest of the setup.

Really want to see what happenes to alu carabiners that has been dropped/throwen onto hard surfaces multiple times to see if it actually weakens it 💪🏽🤔🔥🔥

I think the force at bolt doesn’t add up is because FORCES ARE VECTORS. Dynamic rope and all fractions in the system affect the figures as well

The force on the top bolt should be 2x that of the climber minus the force lost through friction on the top bolt. Without any friction you would see the belayer to have the same overall force, however this just snapshots the peak which could still be different. The force on the belayer is that of the climber minus all the friction, even in the rope. On the Z drag you see very little friction and the numbers almost add up. 2.43*2 = 4.86 The friction on the top bolt is4.86 - 4.78 = 0.08 I don't know what's going on with Mel's long and short falls, but he might have held on to the rope and taken some of the force with his arms.

The forces you recorded were too low and that could actually be dangerous information (= too optimistic). Reason is those dynamometers are designed to record static forces. If small dynamometers like this with resolution of few milliseconds are available I don't know, but would be needed for accurate results. The first symptom of error is that Bolt force is not sum of Belayer + Climber force... Just 5 cents from a mechanical engineer...

Ok those glasses are dope...Those would solve my neck problems belaying

Most people are concluding how hard it is to generate a large force, focusing on the people (belayer and climber). I’m a trad climber and expect/require my belayer to be anchored on multi pitch routes, that test did increase force by reducing the dynamic absorption/offset occurring when belayer is pulled upwards. My focus then goes to the piece of gear catching the fall. Seems 5-6 Kn is going to be common. Some gear is not much more than this AND some placements are definitely a lot less than this. How and what gear you place therefore becomes the most important factor (if that isn’t overstating what should have been obvious to all of us, even before this test). I’d like to see more on forces on trad gear in different types of placements. Maybe on a Big Wall 😀

It doesn't add up due to friction obviously. Energy is lost through the rope rubbing on the biners and wall. Micro(nano?)scopically the rope is literally tearing little pieces from the biners/wall (or visa versa) and that takes energy. That's why the force the bolt sees is never the same as the belayer + climber.

So I guess the 'missing' force is absorbed by the rope stretching. But if anyone knows for sure... (Maybe I should have read the comments more thoroughly)

Hi, I often climb solo on multi-pitches here in the alps, I'd love to know what forces are generated falling when the other member of your party is simply a belay station! The fact is that sometimes I climb on classic routes which have only pitons, and I'm beginning to wonder how these pitons would react if stressed by a serious fall. However, your are great for what you do!

Places were energy is being lost and not meassured, explaining the difference. - Rope drags on the quick draw would heat it up, which would not be meassured. - The rest of the quickdraws on the route, which where not meassured. - Rope absorbs some of the energy of the fall, by streching.

The Reason: the bolt is fixed and can’t transfer the force. Force is not weight.

A 1.8metre fall generates 800 kgf on your body if your body weight is 100kg. I learnt this in my safety harness course over 10years ago. In construction anyway.

How much heavier can you belay. I'm a little guy, can I belay a gorilla, if so, what ratio.

Great job. Also maybe measure actual effectiveness of various jugging systems?

I haven't seen much on the physics behind the measurement, so here's a try. First of all we see, that the climber falls into the rope, that attached to the anchor. On the other end of the rope there are some quickdraws and the belayer. So belayer + friction in quickdraws = force on climber. This explains most of the results: the force on the anchor is approximately double the force on the climber in all cases, because the anchor holds both ends of the rope. The belayer doesn't experience the full force because the quickdraws on his end absorb some force due to friction. Last but not least we must explain the minor differences in comparison to this theory: As mentioned in the video, only the maximum force is measured by every dynometer. But what really had to be absorbed is the energy of the falling climber. Physics tells us E=F*s (Energy equals force times distance) (Precisely this is an integral, which leads to nontrivial mathematics) So if the climber has less rope stretch on his end, his energy is absorbed over less distance than the belayer uses to absorb the energy, resulting in yet a lower maximal force on the belayer's end of the rope. Thus the force is more equally divided and we measure a less high peak force.

The only plausible explanation for the missing force is the angle. The belayer is not exactly below the climber. If the belayer was, say, almost above the climber, the bolt would have had near 0 kNs. So the sum of the two forces would have been far above the force on the bold (and would be meaningless to add them up). What we see is just a less extreme case of the same phenomenon. I also thought of friction on the carabiner at the bolt, but that would just reduce all three forces; they should still add up. Or, the peaks occur at different times. But that is a bit hard to believe. Why would that be. The stretching of the rope does not matter, I think. It would just reduce all three forces.

New to the channel, really like it! The figure of 8 tightening must be a factor in the load measured, meaning the second fall will have a larger load due to less load reduction, J Marc Beverly wrote a good paper describing this effect

I mean... seems kinda obvious that the climber numbers and belayer numbers dont add up, youre measuring the stress on the last bolt but what about the quickdraws before it. My guess would be that belayer+all the quickdraws below the last one+climber = the last bolt... no?

Sorry but you are doing it wrong guys ... :( The max force is obtained when you have a short length of rope, since you are loosing all the elasticity from this rope. This is the reason why a specific damper / energy absorber in via ferrata : you never fall from higher than 1 meter, but the rope is something like 60 cm long

One of the reasons the bolt force is higher than the sum of the belayer and climber forces due to the system friction. That is, the friction from rope drag through the draws and from sliding through the belay device. Petzl did a similar study and found that forces were higher using a Gri-Gri 2 than a tube-style belay device because there was less rope sliding through the device before lockup. This was also extremely evident in the test you did with the the meandering rope path, where the belayer felt almost nothing, while the climber took a hard fall anyway as the rope bound itself against the quick draws. The other factor is almost certainly the nature of dynamic ropes, which are designed to elongate and absorb energy to reduce system forces. I don't fully understand that effect from a kinetics perspective though. If anyone has a source I can read into, that would be appreciated.

My climbing partner is 295 and im 162 - he will belay me (maybe) me on lead soon (start indoor training next month) and im interested to see how hard the falls will be on me 😬😬 - hoping he can hone technique to soften the catch

So, we are really covered with the 25kN on the carabiners.

I’d like to see the worst case and best case. Worst case is probably a heavy climber’s factor 2 fall from above a belay station when belaying from the anchor with an assisted braking belay device. Small nuts are only rated for 4kN, would be interesting to try it on them. Best case is probably a top rope fall or a follower fall on a multi pitch route. Would also be very interesting to see how much softer the fall is with a half rope (and how much harder the fall is with two half ropes).

I suggest visiting a real scientist at the university who might explain the audience some basics on mechanics. Guessing is fun, researching is fact. Especially if you talk/ guess about people’s safety this might be worth it ;)

By grabbing the rope above the load cell you absorb some of the fall force negating the result. You’ve spent a lot of energy in your experiment and proved nothing other than you all grip at different forces. If you were designing something for me I’d fire you the first day……

Let's goooo! This is my home town bro!!! I got to granet arch tho! Pipeworks kinda to expensi,expensive,

I think the dynamic rope aided in absorbing the total weight of the anchor bolt fall which was 3-4 Kn in most cases. In addition to the drag along the line via the drawls. Correct? @hownot2

Guess I'll be the first to say Pinch and Slide is a dated belay style and not redundant, it's not accepted by the AAC nor the AMGA, also bad form to girth hitch the belay loop, that's for hard gear only. I appreciate this was not the point of the video but since this video IS about science we should all use best practices.

Dynamic ropes test, quickdraw slings compared to runners. More climbing gear tests would be nice.

I'm curious to know if the equipment will hold up to someone weighing 230 or up because me and a buddy are around that weight

To describe the difference in forces at the bolts, relative to the sum of the forces at the belayer and climber, you must think in terms of inertia or energy. Both would give the same result, but would paint slightly different pictures. The bolt absorbs the energy that the rope cannot. Or in terms of inertia, the total force is equal to the changes in momentum of the climber and belayer, divided by the time of the interaction. Inertia and impulses are (in my opinion) the best ways to carry out a dynamic analysis of most climbing falls. But sometimes energy principles are slightly more simplistic.

Actually what a good test would be, is how much of a knick on the outside wall (sheath) of a rope would fail. Example one strand, two strands,

What about some falls going up by factors with a dummy instead of a person. Try to break a 10kn 6mm rope

Would be cool to see the forces when hauling on the bolts/anchor and hauler with multiple bags and portaledges. Also the working load forces on the pulley's with a mechanical advantage systems of 2:1 and 3:1.

The peak force on climber + belayer does not add up to force on a bolt, because dynamic rope makes the force more spread in time. If you would calculate integral (sum over the whole fall) you would get the same value. Basically, due to elasticity of the rope climber decelerates faster than belayer accelerates.

so I'm not seeing the advantage of not anchoring the belayer on the first pitch. I think the belayer flying around not anchored is the bigger issue.

Please do something same as this but with onlt three things Bump proof anchor and climber and belayer I mean with no Quickdraws on the wall With 3 meter fall

Long & short falls: in spite of the length of fall, more dynamic rope to extend the period of application in the long fall and constrain the forces on the bolt and belayer so not major differences in the pattern of forces. Static fall: pushed the numbers up by introducing rgidity into the system. Z Drag: made the friction do the work to protect the belayer but in doing so prevented the entire length of dynamic rope coming into action which would otherwise have reduced the force on the climber and the bolt. Big fall: the force on the bolt is reduced because the climber and the belayer are not applying forces to the bolt in the same direction because the fall is at right angles to the line of the rope. (Thought experiment: if he had left the roof and started climbing down the other side then a bolt placed there would have seen almost zero load.)

What distance is the long and short falls above top quickdraw? Thanks!!

Really let's you know just how overbuilt all climbing equipment is to make our sport as safe as possible.

energy is being lost through the rope, absorption through the belayer/climbers bodies and harnesses, and o a much smaller lever frictional forces between materials.

The bolt force should peak a little less than double the climber force. How much less will vary based on the angles of the rope when the force peaks, the larger the angle between the ropes entering and exiting the clip, the lower the bolt force. The belayer force should always be less than the climber force as the reactive force from the fall would be the belayer and sum of frictional forces from clips and the wall. I don't find the bealyer force too interesting on its own, but it provides very interning insite into the frictional forces applied between the belayer and the top clip.

I assume the dynamic property of the rope explains the difference between the dyno readings

I think the bolt experienced more force because it is solid and can’t/won’t move when the fall happens, thus there is no force absorbed as there is for the belayer and climber due to stretch of equipment and the non-static nature of their anchoring.