Metolius TCU climbing cams pulled until failure - Great Slow Motion!

[@HowNOT2]

Purchase Metolius cams at our new store! hownot2.store/tcus

[@stargazer8465]

This channel has helped so much in putting faith in certified equipment. Love what you guys are doing

[@haphaeu]

7:12 at 11.85 kN pull force, the cam is pushing the rock at around 25 kN ! From the video a veeery rough estimate, that rock should weight around 50 kN. So yes, push something with a force of half of its own weight, it should move... For the maths, the force of the lobes pushing the rock is 0.5 * pull_force / tan(camming_angle). Now TCUs have a camming angle of 13.25 degrees, which gives around 2.12 * pull_force. The test had a pull force of 11.85 kN, so you get around twice of that pusing the rock to the side. For the weight, the rock seems to be something like 2 m long, by 0.8 m thick and difficult to tell the width, say 1 m (again veeery roughly), which gives 1.6m³ volume. Rock has around 30 kN/m³, which gives around 50 kN weight.

[@hsoley]

Ok, I disagree, if the pull force is 11.85 kN then the cam or more accurately the friction force between the cam and the rock that is acting in the opposite direction is also 11.85 kN. Since the friction surfaces are two then the friction force on one side is 0.5*11.85 kN = ~6kN

[@haphaeu]

@@hsoley that's correct in the direction of the pull force (in line with the rigging) However to stay in place, cams push the rock perpendicular to the pull force. See at 7:20, "this way" pointing towards the rigging, and "this way" pointing to the sides =) Also have a look on how cams work and you'll see the relationship between the in-line force (these 6 kN you mention) and the cam reaction on the rock (these 25 kN), and you'll not surprisingly find the friction coefficient between the metal and rock: 6 / 25 = 0.24 =) So the total force is indeed the vectors 6kN in-line plus 25 kN perpendicular, which is 25.7 kN. So the in-line force only adds a small component to the total reaction force. The angle of the total reaction force is nearly aligned with the cam reaction force on the rock, just off by a small angle of atan(6/25), which is, surprise surprise, 13 deg, our camming angle =) All that means that cams are designed to meet the friction coefficient required to hold them to the rock. So it is not a "bad design" that cams put so much load onto the rock, they HAVE TO in order to take the climbers fall without sliding.

[@ericthorn]

Since the other side of the rock is so big and not moving at all (can think of it as immovable), the force on the side that moved is actually double that: 4.24*P

[@pl3bx]

I too took physics 1 in highschool lol!

[@Jonslondon]

what??

[@insulterify]

Basically as long as you're not trying to lift a small car you're safe.

[@bbqseitan7106]

Better not climb then 💪🏼

[@phkit420]

Same 🍰

[@TheWtfnonamez]

"Big" car lol. Pretty sure those cams could take care of most compacts. But yeah, if you are trying to dangle your 4x4 off a cliff, I reckon use three of them to be safe.

[@sammyd7857]

Or using slippery cracks!!

[@JohnDoe-bf1fw]

@@sammyd7857 You better remember to pack condoms on the next hike.

[@arkadiuszprusak2007]

I have nver climbed, and probably never will, but man. These videos are extremely watchable. keep up the good work.

[@zurreal9783]

As for someone who is ultra afraid of heights, this is helping me feel abit more safe with the idea of lead climbing

[@cactus445566]

You definitely start off with sport lead climbing first, trad climbing's definitely on the scarier side of things even for intermediate/advanced climbers

[@DrMatthewHudson]

"As far as safety it was super good enough"

[@LucianBlankevoort]

Sponsers HEAR THIS! This is important! I went from just this morning not quite believing in cams completely, to now feeling that I actually do trust them. If this can change my mind, just think how it could increase your market share! C'mon - Sponser this guy!

[@blastfromthepast7119]

You need to trust your placement and the rock. Thin metal stuff, if you still can't bend it, will still hold multiple times your weight.

[@Thurston86]

It Really helps to play with them over n over in safe situations to get to know em and how to place em! After a while of this you’ll know what works and what does not and then your trust will build even more! 🤘👽

[@Jossyish]

Yes. This video and the math comment above enlightened and built some trust in me in cams and rock climbing equipment, especially certified ones.

[@eeeeee9000]

Same, now I don’t trust that cloth sling part though

[@mattjack3983]

@@Thurston86 I completely agree. With your comment and the comments above yours. I already trust the cam to do what it supposed to do. For me the cam was never in question. Its the placement and the rock. And the only way to really know how to trust your placement is, like you said, to spend time playing around with it on the ground..or in a safe situation. After awhile u pretty much develop an instinct for it. Before u even place your cam u already know how good of a placement it is and how its going to sit in there just looking at it. Like every other skill you learn in life, it just takes practice.

[@Cramduck]

1. you could put fiberglassed cement-board in your cam-crusher for rock-lick friction 2. you can use sharpie on the cam teeth to gauge new vs. old damage pretty easily, if that is something that matters to you.

[@morgwai667]

just wanted to leave a word of appreciation for the great value of practical science & field testing that you guys do on this channel!!!

[@lonememe]

Super cool content, thank you for this! After working selling climbing gear for almost 7 years and now being an engineer (not in the industry), this confirms what the industry has been saying forever. Almost all safety gear is over engineered on purpose just to add that extra level of safety. Just take care of your gear, keep an eye on wear, and it'll take care of you for a long time!

[@InterwovenElements]

Thank you for doing these tests. It's fantastic to know that there's an unbiased and non-sponsored source of information on something that is very difficult to learn about in any safe ways that aren't just reading theory.

[@arnoldkotlyarevsky383]

The moral of the story: even your really old cams are super good enough for your average climbing whipper even in slightly mobile rock/uneven placements/multiple break tests/falls. That is actually pretty great to know. Just focus on good placements and solid rock and you might as well be whacking in a bolt. Are cams aid now?

[@danieljay8009]

Always have been aid haha

[@randallladd2370]

@@danieljay8009 Sounds like've sent the pink one in the corner

[@lonememe]

@@danieljay8009 Yep, been used as clean aid for decades!

[@danieljay8009]

@@lonememe the only thing thats not aid is free solo trad climbing

[@danieljensen2626]

@@danieljay8009 I mean if you don't fall and you're only pulling on rock then it isn't aid regardless of your equipment. But yes, falling on a cam has always been aid.

[@weishi4341]

@15:20 how the wire gate opened looks very interesting. I had a recent ground fall after micro nuts popped. One nut landed without being attached to its quick draw, which puzzled me a lot until I saw this. I guess it's possible that the quickdraw gate must have opened during the shock like it did in this video. Thanks Ryan, I really enjoyed your videos.

[@AudreysKitchen]

I found this video because I wanted to understand what these devices are and how they work on an engineering basis. I’m not a climber, I’m a mechanic, but I saw these devices on KZbin and was impressed by them!

[@SuperNova153]

Wow that Aladdin joke made me crack up pretty hard. Thanks for the video!

[@chrisp6582]

For a camming angle of 13.5 degrees the basic rule of thumb is the outwards expansion is twice the pull on the cam. /* start maths: the friction on the cam loads and rock = pullforce/2 (two sides of cam) the load between axle and rock = friction/sin(camming angle) reaction force pushing outwards = friction/tan(camming angle) = pullforce/2xtan(camming angle) tan(13.5) = 0.24 so the reaction force pushing outwards = 2.08 x pulling force */end maths

[@muchmore344]

at 5:25 the engagement angel looks like ~45° I guess 13,5° is the max angel ?

[@tomtom4405]

I was scratching my head for ages before I posted. With you on tan angle, but I'm thinking real life and pull not perfectly central (worst case) you have a behaviour where the cam(s) on one side doesn't rotate on shaft but rather just pivots/rolls over the rock and the cam(s) on the other side does the camming. That case I think you have a mechanical advantage of 1/0.24 (roughly 4). Interested in why you say approx 2 not approx 4, because I've been thinking about this for a while and still head-scratching a bit :)

[@chrisp6582]

@@tomtom4405 Its because the load on the cam is distributed to both sides of the crack, with each side holding approximately half the load. The best way to see it is to draw a force diagram and you will see you need two frictional forces and two reaction forces (one for each side). In the case where the lobes are unevenly rotated so the axle is not central because of the constant camming angle the triangles used for the force calculation remain the same shape, even if they are different sizes. The cam may roll/pivot as the load is taken up, as the axles are slightly elastic and the rock may deform under the stress, but both sides are engaged and are applying an expansive force which relies upon the friction. Imagine if one side of a crack was perfectly smooth (mu = 0), the cam would not be able to engage and would just slide out. This (hopefully shows) both sides are needed in order get a camming action.

[@tomtom4405]

@@chrisp6582 thanks, I'd thought about this originally but I'd misunderstood the scenario of one cam not rotating on shaft. You're absolutely right. Even if one cam rocked but not rotated on shaft because of the log spiral it still expands by 13.5 (or 13.75 wild country) degrees. So it is always 2 cams/sides expanding. 1/(2*tan 13.5) is approx 2. Thank you for correcting me!

[@chrisp6582]

@@muchmore344 Hi Matthias, It looks like the cam is contacting the rock at roughly where the trigger wire is attached to the cam lobe. I'd guess the angle was approx 20 degrees but it is hard to tell. The 13.5 degrees is the camming angle in a parallel sided crack. Of course in nature cracks may not be perfectly parallel which would change the angle.

[@dylancole3861]

I don't climb or have any idea what this is but for some reason I'm watching this

[@JoshuaTootell]

Those things are used when rock climbing. Put those in a crack in a rock, clip your rope to it, and keep climbing. The person climbing behind you on the same rope pulls it out. If you fall, this thing is what keeps you from dying.

[@xvillin]

4:30 you knocked that bug out. He fell right off.

[@gabriellynn4418]

Lmao, that comment @ 6:00 in regards to the movie Aladdin caught me off guard!! I looked it up though and you're not wrong at all, hahaha!

[@simold13]

Thanks! Would love to see cams tested with the stem not aligned with the direction of pull. Might take some doing to test this, but would be super fascinating to see cams put under rotational load.

[@AZDesertExplorer]

Having a bunch of second hand Metolius cams always sketched me out. Watching this & your previous video has me a lot more confident in my gear, I mean, if it’s in serviceable condition why replace it? Super good enough!

[@Luke00722]

Same, might start using a few of my old favorites because of this.

[@JesseUnderscoreMartin]

15:19 Check out that gate flutter. Pretty cool slo-mo shot

[@koltface]

WOAH! Good eye! That's pretty crazy.

[@Ric_Teixeira]

And they say that wiregates don't flutter...

[@MrJoebass702]

@@Ric_Teixeira That is my thought exactly!! Yikes! Looks like it was only wishful thinking.....

[@ML-fc3je]

Not a climber just discovered this channel and I always appreciate testing products in field. Yes laboratory tests are important for ease of controlling variables to duplicate results but its also important to note even the best laboratory test won't be able to predict all variables.

[@AnttiPohjola]

some Brittish trad climbing books suggests that the cam should be inserted into horizontal crack by keeping the outer cams downwards, and it should be stronger. Maybe you could also test if it's true.

[@timothydraper3687]

Perhaps that makes it less likely to walk it's way out?

[@marcokawasaki]

I don't know why YT suggested me this, but it was actually quite interesting!

[@MrRaandom]

I'd love to see cams tested in dirty and wet placements! (Also looking forward to flared cracks.)

[@rikvdmark]

Nice, thanks for all the effort you guys put in testing all this stuff 😁

[@ChristianOudard]

Appreciate your work keeping people informed and safe.

[@stephenr80]

15kn with a messed up cam, shows how important a good placement is and how tough those boys are

[@jonflannery8984]

I would just like to comment the obvious by saying all cracks in rock are from the rocks moving. Thanks for sharing more awesome content.

[@TheArmyKnifeNut]

20:33 "Sometimes pulling out can damage the crack, so therefore, you shouldn't climb." or "Sometimes pulling out can permanently deform what you pulled out, so therefore, you shouldn't climb." or "Sometimes pulling out can leave some cam behind, so therefore, you shouldn't climb."

[@radbikeshredgnar4423]

I've been waiting for this since I started watching. Siiiick! Thanks dudes!

[@davide5429]

Very interesting channel, I'm subbing now. It's what I've always been wondering while climbing

[@TheManCave563]

Learned something new as always so take my donation! Maybe do tricams passive and active mode. I really rate them but I'm the only one in my climbing group that has them so it would be nice to sing the praises!

[@brentknickerbocker6023]

Great content; donated. More rocks types, more cams, and more varied placements.

[@HowNOT2]

Thanks! Will do! I also want a faster dyno and will drop test them too

[@shanemeyer9224]

hopefully this helps ease anyones mind when they question a Cam, this thing moved a rock that is tons, i happily trust my life on well placed cams during climbs

[@DriedMoss]

It’s impressive that the only reason the cam got out was because the rock opened up

[@rosschristensen4394]

Great Channel, Love it, keep em coming!

[@mcfjk3]

Put an ascender on the line that you're pulling to tension the system! Might make it a little more comfortable for you to pull. Great content! Thanks guys!

[@b0mazor]

"These cams are reliable, these rock's aren't budging"

[@mountainmandoug]

It is very difficult to analize the pulley system from what you show in the video, but from the pullers to the load I think it is a 3 to 1 times a 2 to 1 times a 5 to 1, and I think that adds up to 30 to 1. The grigri is a major source of friction though, and it's location makes it hard to calculate it's effect on the overall system, in practice it may reduce the adavantage to more like 20 to one. I think the most efficient system with the equipment you showed would be to rig a 3 to 1 with the pro trax as the progress capture and the big SMC single as the traveling pulley, and then stack your double pulley system on that as a complex multiplier. You certainly made the cams look good, it seemed like everything broke well above rating, as Metolious cams are labeled 10kn. Are those the original slings? Funny how Bobby managed to get the stronger placements, maybe you guys should make a video where you argue about the cam placements, and then pull-test to see who is right.

[@caedmonswanson7750]

I think if the sling breaks you should put a soft shackle around the the actual wire so that the small bend radius of a Carabiner doesn't cause the wire to break.

[@sunchips11]

That, or even using two or three carabiners through the wire to increase the bend radius.

[@turning5462]

A bigger radius is not a realistic test. Climbers would only have a carabiner.

[@caedmonswanson2378]

@@turning5462 You would never put the carabiner in the wire loop. You learn that day one for the exact reason showed here, it breaks easier.

[@Magenta-_-x]

This channel is awesome.

[@NNPerfection]

Thanks again! Great content!

[@GregSidberry]

Thanks for all the testing. Would love to see tricams tested in active mode

[@redbrandonk]

I'm impressed with the consistency you got there. looking forward to trickline break tests

[@HowNOT2]

doing it next weekend!

[@azaba2007]

can't wait for the tricams test.

[@jtveg]

Thanks for sharing. 😎👌🏼 Especially for *_The Bolting Bible._* 🔩🔨🔧 🗻

[@ericlakota6512]

I like how you trusted that yellow string i yousw that for my buck strap whene climbing

[@thedoddfishtreemonkey.7760]

In 2001 after 911 I ended up at Pickle meadows as an instructor. And I spent a lot of time doing something like (but not as vicious) this to find what kit the military were going to buy for Afghanistan. They went with HB in the UK then DMM later on.

[@prestonberry4695]

I would have never guessed that cams were that strong

[@tuanoful]

It's amazing how much those things can hold

[@interestedinstuff]

I had no idea cams were so reliably stubborn about letting go. This channel should totally get some sponsorship off the cam folk. Also makes me think cams should get an extra sling. Ha.

[@deranged1925]

1 pound is 0.00444822 kilonewtons (his force unit). At 5:24 he says it was at 11.5 kilonewtons...that is equal to a 2585.303 pound force. Cams are truly reliable.

[@whateverihateyouwtf]

that rock totally moved at 10:40. i thought i imagined it until i watched it a few more times

[@HankMil]

Test Request: check out this video at minute three. He prefers a cam with an extendable sling, and saves the extra wire gate! Is that stronger as he believes? I am happy to contribute one new sling. Hope if more people contribute, this test can be free on your side + Bonus!!!! Let me know what you think, please. And thank you for the content, I was studying climb accidents in College. Dude BFThanks!

[@danielg8118]

Try pulling out tricams used as chocks and as levering mode

[@Nasogaa]

would be intresting!

[@danielg8118]

@@Nasogaa yeah I use em a lot it would be really nice to test them

[@SlavaThereshin]

I never trusted cams, but now I do… guess now I just have to donate. Where's that coffee?

[@spaight711]

Easy idea for the slack-snap out of rock. Granite countertop dealers will sell you the pieces from sink cutouts for dirt cheap and then you can fabricate your plates to hold them. Usually, the bottom side of the material is rough,

[@jamierice9211]

15:57 Ryan pretending to pull on the rope ahaha

[@zacharyrodenbucher9977]

It's clearly a super-good-enough to one, because inefficiencies in the system throw the theoretical multiplier out the window, and it was enough to do the job.

[@HowNOT2]

i love it! haha

[@garisonvaber3877]

The lateral force by a cam goes as 1 over the tangent of the angle formed by the contact point and the axle, call it theta: F_lat=0.5*F_ax/tan(theta). That angle is a design variable which depends very much on the anticipated coefficient of friction--the lower the friction, the smaller that angle must be to hold. A cam will NOT work without some friction to keep the lobes from slipping and thereby force the cam rotation harder into the wall. For example, cams don't work on polished granite. This theta angle is typically around 15 degrees and remains about constant with cam extension for parallel sided cracks. In this case of about 11kN axial force, the lateral force would therefore be approximately 21 kN (4700 lb).

[@dragan3290]

Damn that's awesome! Love your tests!!!!🙂👍👍👍

[@GrigoraAus]

ROFL why is Ryan pretending to pull on the rope at 16:32 when bobby has to do all the hard work :P Keep up the great work guys

[@HowNOT2]

Just to see if you are paying attention :)

[@casiopistachio1107]

How much force does someone make on these cams if they fall a long way, for instance 15 meters?

[@danieljensen2626]

A quick internet search suggests 2kN-5kN from a big fall, so even those smashed up cams would get the job done if the placement is good (although obviously not recommendable to use something that is basically destroyed)

[@cunderwood1992]

5:27 the whole rock is moving!!!

[@lazyman2604]

That was wild 😳

[@Ilindariel]

For the tests in your garage, you could screw two 60-80mm granite plates (rough) onto the metal jaws. use threaded rods and Injektionsmörtel HIT-HY 200-A or sometink like it.

[@tryAGAIN87]

This just tells me that cam placement is better in horizontal cracks rather than vertical cracks. Vertical cracks can be levered with less force than it would take to lift the mass of the rock itself. Whereas, horizontal placement means you would need to overcome the entire mass of the rock to have the cam slip out.

[@luigibenignochiappero5589]

Master : Super good job!!!!!!!!!!! CONGRATS !!!! CHAPEAU!!!! TANK YOU!!!!! BEST WISHES.

[@tomtom4405]

Edit: see Chris Powell reply for correct explanation. Expansion is double pull not 4 as cams expand both side. Not 1side as my following post calculates. Thanks @Chris Powell ------ (1/tan 13.75 degrees is roughly 4). So if your cam is pulled 11.85kN then you are putting about 4 times that pushing apart, about 47kN, to expand the gap. Cams are great, but even slightly shaky rock can shift sometimes.

[@davidvigneux6929]

4:32 man that ant must've shat itself!

[@TheMacgyver3441]

These things are stupid strong. I had no idea. Use 3 of them and you could lift my boat out of the water. That’s insane.

[@yazmat96]

the poor ant at 4:36 is like: wtfk dude? :D

[@malcopops4]

I'd be interested in seeing what kjnd of poor placements will slip out at 4kn. Like how bad does your placement need to be to be a problem.

[@lucyxchan6808]

"We can put it in deeper and try again" ~HowNOTtoHIGHLINE

[@PeregrineBF]

I don't have or use Facebook, but will have some gear to send (a set of C.A.M.P. Dyneema Tricams, and several example bend/loop knots in Edelweiss 7mm accessory cord, maybe splices in same if I can get them decent with the thin sheath).

[@benja_mint]

good onya! i use the same tricams so i'd be excited to see them get tested

[@HowNOT2]

hit me up on email [e-mail]

[@Geolaminar]

As someone who knows nothing about climbing, and only a bit about physics (high school)... Keep in mind that shock loading can be up into the tens of gees. So a very big dude falling on a unsafely stiff rope might BARELY edge out a failure (100 kg * 100 m/s^2 = 10kN). Or worse the cam lobes might not dig in right from the shock loading? Either way, even if the cam holds, at those accelerations there's a pretty good chance the rope jerk just snaps your spine... So there are other problems

[@TheRedWon]

I would have used that rock to make an anchor before I watched this video! Pretty crazy to see it move like that. Would have held if the follower fell but still. . . .

[@lucasschofield8716]

5:27 the Cam didnt give up, it actually moved the rocks apart.

[@wb5mgr]

According to factory testing Petzl has done they say an anchor experiencing a FF 1 fall could see as much as 6kn of dynamic load +\- .5 kn. Interested in how that lines up with your tests? If that is true, there is a generous safety factor designed into these cams. Makes one feel a lot more confident using them.

[@z1522]

Backing all the way out, to just thinking about placing gear for protection - a simple nut in a good tapered placement also exerts wedging force, but the friction against the walls might be higher, so expansion might not be observed. It looks like that particular rock could be slung around the other end, a perfectly useful way to get a directional anchor that exerts just a single pull, with no multiplications from cam leverage, etc, and as it weighs several tons, one could expect to trust it. Except, that if it were poised on a near balance point, the force needed to rotate it might be a small fraction of its total weight. Thinking about how each situation has potential weaknesses can be sobering. Making a habit of placing even cams into tapers and not just blindly into parallel slots can make much more reliable protection.

[@sanebedlam]

Talking about the bend radius issues on the cable I wonder if doubling up carabiners might help?

[@GodzillaGoesGaga]

The metal wire will still bend over the edge of the carabiner. That's the bend radius he's referring to.

[@danielquiroz1884]

I don’t climb but always wondered how these little metal hooks can hold and stop someone from falling to their death. Pretty cool lol

[@ancientserpent3550]

your knowledge is not killing people

[@grelgen]

16:00 is it me or did the top rock move?

[@ProjectMaelstrom]

So what I learnt and keep from this video is that the rock will most probably fail before any good equipment. And nooooow I am afraid of the rocks instead of having fear of equipment failure 🤣🤣🤣

[@HowNOT2]

That was our takeaway too.

[@patob3363]

Curious. You said those are 15 years old. Have you had the slings replaced in that time?

[@Alyogyne1]

Looks like the original slings to me - I own a few of similar vintage.

[@HowNOT2]

Original Slings

[@pole131]

@@HowNOT2 so what could a re-slung cam hold? They say nylon looses strength over time and with UV exposure.

[@StuartCGrossman]

Sick work. Test totems 😉

[@noah_9886]

You should slack snap one of those expandable tube pro for offwidth

[@asterixzm]

18:05 is big Rock moving?

[@EnigmaticPeanut]

i love what you are doing. its very useful.

[@EnigmaticPeanut]

me and many other rely on technology like this to keep us safe at work, so without these tests, we just rely on what we are told : "it should be safe". With what you are doing, we can actually see and know what are the limits, it truly helpful.

[@rafsonpodczele]

Dobra zabawa połączona z nauką , pozdrawiam 👍 🇵🇱

[@lloydkocourek8988]

Bobby is awesome

[@FL-gg4dq]

@4:36 that 🐜 is my client. We are suing for damages

[@RichardBronosky]

These videos are great! You should get some granite off cuts from a countertop installer. The underside is fairly natural texture.

[@goodbyemr.anderson5065]

What would be the point of that? Countertop cut off are not gonna weight enough to test anything.

[@RichardBronosky]

@@goodbyemr.anderson5065 not for weight. To use as the contact surface for the cam. Test cam against stone instead of cam against metal.

[@travisk5589]

12:53 Wow. That rock moves a little. Look left of center on the crack. it drops back down.

[@pavlodeshko]

Please test some metolius cam placed in "red zone" (dots on the lobes). Cheers!

[@gdalmuti]

Agreed. My rule of thumb is that the hardware is built "strong enough" (as these tests bear out). What worries me are marginal placements like tipped out cams, flared cracks, shallow placements, placements where the cam is forced out of alignment with the direction of pull, etc.

[@Voiced606]

That poor bug at 4:30 when the rock broke lol

[@stevenrs11]

Perhaps put the line scale in the pulley stack?

[@7thrx]

I think this speaks a lot about working with gravity. You might want to only use horizontal cracks because the weight of the rock pushes down on the cam. With vertical cracks you don't get the same force of the rock pressing down.

[@MrCorp53]

If you are talking about a boulder, I'd agree, but for cracks in large rock faces, this makes absolutely no difference.