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Edelrid MegaJul Belay Device

NC Rock Climber · · The Oven, AKA Phoenix · Joined Dec 2009 · Points: 60
rgold wrote: No, it is precisely the kind of discussion and testing that goes into the production of the devices you use, given by someone who is in the business, who was responding to an explicit request (from me) for that level of information. You are evidently blissfully unaware of these design processes, and you may not understand any of it, but you benefit from the fact that someone is doing it, and when you go out to the sport crag and catch a factor 0.1 fall with your device and proclaim that's all the testing anyone needs, you had better be grateful that someone has put more thought into it than that, engaging in precisely the "bullshit" you're ranting about. Jim's only sin is that he was willing to take the time to pull back the veil and give us some insight into how he arrived at his statements. He only did so because I asked him if he would. In some other places, the "bullshit" he provides is called a rational explanation for observed phenomena. You get a guy who is an expert in the field willing to take the time to explain how certain things work---that's a privilege. Let's drive him away with cries of "bullshit" so we can go back to the process of obtaining real understanding from our highly sophisticated and fully comprehensive testing at the sport crag with a tiny leader fall or two. In any case, Jim's post isn't required reading---you are free to skip it and use the time saved to eliminate the general level of bullshit by promulgating more arbitrary posting restrictions.
+1

Jim Titt and Rgold consistently post quality material. You don't have to agree with them, but referring to their posts' as "theoretical mathematical bullshit" is the height of total fucking stupidity. Yes, Brian, I am talking to you. You don't have to agree with what they say, but to deride their their post with such moronic rhetoric reflects more on you than it does on the content their posts.

FWIW, I have been using the Alpine Smart for about 3 months now. I like it a lot and believe that it provides more breaking force than an ATC. HOWEVER, if there is a situation where this device will provide less braking power than an ATC, I would like to know about it.

Thanks, Jim, for posting up your findings on how these devices actually function. I look forward to reading more about any further testing that you do.
Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 804

Only on a climbing forum can you make a recommendation on a piece of gear that you have never personally used. That is total bullshit, like it or not.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

I think before we leave this fecally infected thread, a bit of review is in order. What I wrote way back when was

rgold wrote:Personally, I wouldn't be in a rush to embrace the MegaJul. As a counterpoint to the raves here, I know a handful of people who have tried them and don't like them. Its performance appears to depend a great deal on rope diameter and the carabiner that is used, so it is a bit hard to know what you are actually getting. It is known to be hard on carabiners, and the earlier models had quality-control problems (these may now have been fixed however). The primary advantages seem to be light weight, small size, and modest price.
Brian would most definitely have a point if I had pretended to give a recommendation based on personal experience when in fact I had none. But in this case I reported the opinions of experienced climbers I knew and appended, in addition to their opinions, things I knew from the previous MegaJul thread. Everything I said was honestly presented, and everything I said was and is true.

At this point it is up to you, dear reader, to decide who is truly full of it. As for me, I find my colon to be clear, figuratively speaking of course.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Brian wrote: So are you saying that an ATC is going to hold a factor 2 fall any better than a MegaJul? Especially without gloves on the belayer? Have you actually used a MegaJul or are you theorizing too?
The instructions for the MegaJul explicitly tell you to use an intermediate protection point to eliminate F2 falls. Whether this is merely caution or shows their knowledge of its capabilities is something only they can tell you. I specifically mentioned F1.9 falls for this reason.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Brian wrote:This is exactly the theoretical mathematical bullshit I'm talking about. Go out to your local sport crag where your partner is going to fall a lot and actually use a MegaJul. It will autolock and catch your falling leader every time. I've actually used the device for a couple of months now and that is my real life experience with the device. I don't know the exit or entry angle. I don't really care. It caught the leader every time on some pretty big whippers. That is what you should care about. Is it fool-proof? No. No device is but if your belayer is inattentive or gets hit in the head with a rock it is a nice to have an auto-locking/assisted-locking device instead of the rope screaming uncontrolled through the ATC.
For "pretty big whippers" down your local sport crag any belay device will do. 20m out on some gearless horror show and you´ll be looking down at your belayer and hoping the one he´s using will. You can extend your ùser experience´ experience with the MegaJul by going to the top of your local 100m cliff and throw yourself off and tell us about it OR accept others will have to use their experience, testing equipment and theoretical anylysis to tell the world what really happens.
Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 804
Jim Titt wrote: For "pretty big whippers" down your local sport crag any belay device will do. 20m out on some gearless horror show and you´ll be looking down at your belayer and hoping the one he´s using will. You can extend your ùser experience´ experience with the MegaJul by going to the top of your local 100m cliff and throw yourself off and tell us about it OR accept others will have to use their experience, testing equipment and theoretical anylysis to tell the world what really happens.
Okay, why don't you use your "experience, testing equipment, and theoretical anylysis" (sic) to test the MegaJul against an ATC and report back your findings instead of commenting on a piece of gear you've never used? Any reasonable person would find giving advice on a piece of gear you've never used to be highly questionable.

First question you can test is: "20m out on some gearless horror show" (factor 2) will an ATC belayed off the waist hold a fall any better than a MegaJul? My bet is that a MegaJul will hold better because of its "assisted locking" than an ATC especially if the belayer does not have gloves on. Of course that is just speculation. It is yours to test.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Brian wrote: Okay, why don't you use your "experience, testing equipment, and theoretical anylysis" (sic) to test the MegaJul against an ATC and report back your findings instead of commenting on a piece of gear you've never used? Any reasonable person would find giving advice on a piece of gear you've never used to be highly questionable. First question you can test is: "20m out on some gearless horror show" (factor 2) will an ATC belayed off the waist hold a fall any better than a MegaJul? My bet is that a MegaJul will hold better because of its "assisted locking" than an ATC especially if the belayer does not have gloves on. Of course that is just speculation. It is yours to test.
You are confused, I posted "I don´t use it even though I have one." which means exactly what it says. I have used it previously along with the Alpine Smart and I don´t use that either, in fact I´ve maybe 30 different devices that I have used to field test but don´t use as my personal belay device.
I´ve already told you, the MegaJul is weaker in high force falls, as are the Smart and the BRD.
Incidentally I too believed this type of belay plate was more powerful and used one (Smart)for 7,8´s on my last trip to the States. A couple of months or so back I was testing the gripping abilities of belayers with single and double ropes and wearing gloves or not and the Smart and then the others got flung into the test and proved not to be what I and most others thought.
Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 804
Jim Titt wrote: You are confused, I posted "I don´t use it even though I have one." which means exactly what it says. I have used it previously along with the Alpine Smart and I don´t use that either, in fact I´ve maybe 30 different devices that I have used to field test but don´t use as my personal belay device. I´ve already told you, the MegaJul is weaker in high force falls, as are the Smart and the BRD. Incidentally I too believed this type of belay plate was more powerful and used one (Smart)for 7,8´s on my last trip to the States. A couple of months or so back I was testing the gripping abilities of belayers with single and double ropes and wearing gloves or not and the Smart and then the others got flung into the test and proved not to be what I and most others thought.
"...MegaJul is weaker in high force falls..." What do you mean by that? It is going to break or it doesn't lock off as well as a tuber? How weak? In a real-life scenario is it going to break? Are you referring to belaying off the waist or in guide mode?

:"...proved not to be what I and most others thought..." What does that mean? So are you are saying a belayer without gloves can hold a fall better with an ATC than with a MegaJul?
reboot · · . · Joined Jul 2006 · Points: 125
Brian wrote: "...MegaJul is weaker in high force falls..." What do you mean by that? It is going to break or it doesn't lock off as well as a tuber? How weak? In a real-life scenario is it going to break? Are you referring to belaying off the waist or in guide mode? :"...proved not to be what I and most others thought..." What does that mean? So are you are saying a belayer without gloves can hold a fall better with an ATC than with a MegaJul?
Jim made this pretty clear already, but here's a simplified "theoretical math" explanation:
A belay device (sort of like a pulley) has a coefficient of efficiency:

fall_force x C_1 = required_hand_brake_force_1

This mostly depends on the bend angle of the rope (and the groves) thru the device.

Now you have this "brake assist" feature that provides at most A_f amount of brake force:

fall_force x C_2 = required_hand_brake_force_2 + A_f
or
fall_force x C_2 - A_f = required_hand_brake_force_2

but to make it engage easily, you have to increase the belay device's coefficient of efficiency. It's easy to see how

fall_force x C_1 < fall_force x C_2 - A_f

if C_1 < C_2 and fall_force is high enough.

Edited to add:

My understanding is something like a Grigri is different in that it's a camming device that increases the assisted brake force with increased fall force. With the right diameter of rope, your hand is there primarily to engage the cam should it not engage by itself. However, the Grigri has a reasonable amount of braking power (equivalent to a worn ATC) even if the cam doesn't engage vs a Cinch which has virtually no braking power w/o the cam, making the latter quite dangerous.
coldatom · · Cambridge, MA · Joined Sep 2011 · Points: 70
NC Rock Climber wrote: Jim Titt and Rgold consistently post quality material.
+1
rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

For others interested in this, Jim hasn’t got (or at least hasn’t shared) a mathematical model of assisted braking belay device performance. I don’t think reboot’s works for a number of reasons, but that discussion isn’t relevant here because we are not debating mathematical models.

Jim has some load measurements and some physical explanations in terms of rope angles in the devices. He is, I believe, using the term power the way reboot has used efficiency, i.e. how much the device multiplies the applied hand force. His tests so far suggest that at high loads, the tested assisted-locking devices actually have a lower hand-force multiplication factor then an ATC-XP.

My understanding—which may be all wrong in which case Jim will, in the fullness of time, correct it—is that the assisted locking action can occur before the carabiner travels all the way to its highest possible position in the slot. If this happens, and if the load increases enough, the carabiner is pulled further up, which decreases various rope bend angles and so decreases the “power” of the device. Perhaps it isn’t simply a question of carabiner position up or down the slot but also a question of the angle of the belay device under increasing loads, and perhaps both of these possibilities work in concert.

The consequences of all this aren’t clear to me at the moment. I don’t know whether Jim has taken static measurements at an increasing range of loads or somehow studied the dynamics of the device behavior under high fall-factors. I don’t know how much the decreases in “power” might actually matter. If they do matter, I don’t know what the comparison is between rope run through an ATC and rope run through an assisted locking device for high fall factors. The assisted-locking feature might force the rope to absorb more fall energy before running and so lead to less rope running through the device when it does run, even though the power of the device is less at that point. Or, on the other hand, the rope running after a momentary apparent locking could be a surprise that causes the belayer to lose control.

Most of us think of a belay device as a simple gadget that adds friction and so multiplies grip strength by some constant. Indeed, quite a few papers have been written on belay dynamics include this assumption. But as the devices get more complicated, this assumption may no longer be valid, if it ever was, and this is what Jim’s results so far are suggesting. Whether those results have practical consequences for adopting such devices, and/or whether those results inform the way the devices are employed, remains to be seen.

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

the mammut smart (and alpine smart) is NOT autolocking ... it provides an assisted lock ... you treat it like an ATC+ and always keep your hand on the brake (which you should with a gri gri as well)

it can and will slip should the rope be thin enough, new and slick enough, etc ...

on a single line rap on a mammut 9.5 or beal 9,7 it does slip ....

on falls it locks most of the time, but there will be times when it does slip

IMO on "normal" falls its provides more breaking power than an ATC ... and on a 10mm rope which i use for most things it locks more reliably

i own and use all versions of the smart extensively every day

ive used the megajul somewhat when my partners have em ... it feeds and works around the same as the smart IMO ... but rapping on the assisted mode is a biatch without unless you use that biner as lever

and the autoblock is a biatch on anything approaching 10mm ropes

the alpine smart pulls through the device in autoblock like buttah

i havent had the opportunity to test either in high factor falls on real rock ... thank god

but i would definitely like to see the actual data on these braking device on such falls

;)

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Brian wrote: "...MegaJul is weaker in high force falls..." What do you mean by that? It is going to break or it doesn't lock off as well as a tuber? How weak? In a real-life scenario is it going to break? Are you referring to belaying off the waist or in guide mode? :"...proved not to be what I and most others thought..." What does that mean? So are you are saying a belayer without gloves can hold a fall better with an ATC than with a MegaJul?
Weaker as in the braking power obtained relative to a given belayer hand force and relative to the ATC XP belaying from the harness using the accepted standard belayer input/faller rope output angles (that is belaying normally) using the ropes I have tested with.
The breaking strength of the device is tested under EN15151.
The ATC XP has no guide mode.
A large fall yes, a small fall no.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
bearbreeder wrote:the mammut smart (and alpine smart) is NOT autolocking ... it provides an assisted lock ... you treat it like an ATC+ and always keep your hand on the brake (which you should with a gri gri as well) it can and will slip should the rope be thin enough, new and slick enough, etc ... on a single line rap on a mammut 9.5 or beal 9,7 it does slip .... on falls it locks most of the time, but there will be times when it does slip IMO on "normal" falls its provides more breaking power than an ATC ... and on a 10mm rope which i use for most things it locks more reliably i own and use all versions of the smart extensively every day ive used the megajul somewhat when my partners have em ... it feeds and works around the same as the smart IMO ... but rapping on the assisted mode is a biatch without unless you use that biner as lever and the autoblock is a biatch on anything approaching 10mm ropes the alpine smart pulls through the device in autoblock like buttah i havent had the opportunity to test either in high factor falls on real rock ... thank god but i would definitely like to see the actual data on these braking device on such falls ;)
That about sums it up really. The one feature which I thought the Smart does better than the rest is guide mode even though I never use this feature.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
rgold wrote:For others interested in this, Jim hasn’t got (or at least hasn’t shared) a mathematical model of assisted braking belay device performance. I don’t think reboot’s works for a number of reasons, but that discussion isn’t relevant here because we are not debating mathematical models. Jim has some load measurements and some physical explanations in terms of rope angles in the devices. He is, I believe, using the term power the way reboot has used efficiency, i.e. how much the device multiplies the applied hand force. His tests so far suggest that at high loads, the tested assisted-locking devices actually have a lower hand-force multiplication factor then an ATC-XP. My understanding—which may be all wrong in which case Jim will, in the fullness of time, correct it—is that the assisted locking action can occur before the carabiner travels all the way to its highest possible position in the slot. If this happens, and if the load increases enough, the carabiner is pulled further up, which decreases various rope bend angles and so decreases the “power” of the device. Perhaps it isn’t simply a question of carabiner position up or down the slot but also a question of the angle of the belay device under increasing loads, and perhaps both of these possibilities work in concert. The consequences of all this aren’t clear to me at the moment. I don’t know whether Jim has taken static measurements at an increasing range of loads or somehow studied the dynamics of the device behavior under high fall-factors. I don’t know how much the decreases in “power” might actually matter. If they do matter, I don’t know what the comparison is between rope run through an ATC and rope run through an assisted locking device for high fall factors. The assisted-locking feature might force the rope to absorb more fall energy before running and so lead to less rope running through the device when it does run, even though the power of the device is less at that point. Or, on the other hand, the rope running after a momentary apparent locking could be a surprise that causes the belayer to lose control. Most of us think of a belay device as a simple gadget that adds friction and so multiplies grip strength by some constant. Indeed, quite a few papers have been written on belay dynamics include this assumption. But as the devices get more complicated, this assumption may no longer be valid, if it ever was, and this is what Jim’s results so far are suggesting. Whether those results have practical consequences for adopting such devices, and/or whether those results inform the way the devices are employed, remains to be seen.
Complex is the way to describe what happens in the various active belay devices, just using simple lever theory a Grigri doesn´t really work and they will actually slip at very low loads and rope speeds which is a well documented feature, put the load on and they hold like mad. On the other end something like a Cinch locks up really hard under small fall conditions but slips considerably with high rope speed. We think we know why this is but what´s actually happening at the pressure point in a Smart or MegaJul is something to look at more carefully. The simple explanation is that the incoming rope resists the karabiner applying additional force to the pinch point but that´s a rather complicated thing to explain here.
The braking force related to hand force is actually quite consistent for both conventional plates and the MegaJul, just the latter starts higher but increases less. I´ll produce a graph of this when I´ve tested the Smart the same way for comparison.

If I manage to get my drop tower out of the weeds where it´s lying and do some more dynamic testing then we´ll see what we can find out but finishing my bathroom is more a priority somehow (at least my wife says so).
Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 804
Jim Titt wrote: Weaker as in the braking power obtained relative to a given belayer hand force and relative to the ATC XP belaying from the harness using the accepted standard belayer input/faller rope output angles (that is belaying normally) using the ropes I have tested with. The breaking strength of the device is tested under EN15151. The ATC XP has no guide mode. A large fall yes, a small fall no.
I meant Black Diamond ATC Guide.

So in a factor 2 fall the assisted locking of a MegaJul doesn't lock-up and assist in braking and the rope in any way and the rope will go screaming through the device as rapidly as a regular ATC? And a BD ATC is easier to hold a factor 2 fall? Unless we are talking about different things, I find that to be incredible. I probably can't convince any of my climbing partners to take a factor 2 fall for me to test it so I will have to continue to disbelieve it until I see verifiable published tests.
NC Rock Climber · · The Oven, AKA Phoenix · Joined Dec 2009 · Points: 60

Jim, thanks for posing up all the info. I really appreciate it. Just to make sure that I am clear, you are saying that the Jul / Smart will hold a "small" fall with less hand force from the belayer that an ATC. However, an ATC will hold a "bigger" fall with less hand force from the belayer that a Jul / Smart. Is this accurate? Also, do you know at what point the Jul / Smart requires more hand force that an ATC?

In my experience with the Smart, the exit angle of the rope from the device makes a big difference in the amount of hand force from the belayer that is required. If directly under the first piece, less hand force from the belayer is required. The greater the angle between the belayer and the first piece, the greater the amount of hand force from the belayer that is required.

Edit to add...
performance in factor 2 falls is not something that I am concerned about. I set up belays so that a Factor 2 is a VERY low probability. I always have the rope running through a piece above me, so a factor 1.9? is about as big as I will ever need to hold. If I am worried about a true factor 2 (which is virtually never), I will use a grigri. My concern is generating stopping power where the direction of pull is up.

Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 804
NC Rock Climber wrote:... performance in factor 2 falls is not something that I am concerned about. I set up belays so that a Factor 2 is a VERY low probability. I always have the rope running through a piece above me, so a factor 1.9? is about as big as I will ever need to hold. If I am worried about a true factor 2 (which is virtually never), I will use a grigri. My concern is generating stopping power where the direction of pull is up.
+1
But I still can't believe that an ATC will hold a factor 2 fall easier than a assisted braking device. I sent Edelrid an email to see if they have any tests on factor 2 falls.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
NC Rock Climber wrote:Jim, thanks for posing up all the info. I really appreciate it. Just to make sure that I am clear, you are saying that the Jul / Smart will hold a "small" fall with less hand force from the belayer that an ATC. However, an ATC will hold a "bigger" fall with less hand force from the belayer that a Jul / Smart. Is this accurate? Also, do you know at what point the Jul / Smart requires more hand force that an ATC? In my experience with the Smart, the exit angle of the rope from the device makes a big difference in the amount of hand force from the belayer that is required. If directly under the first piece, less hand force from the belayer is required. The greater the angle between the belayer and the first piece, the greater the amount of hand force from the belayer that is required. Edit to add... performance in factor 2 falls is not something that I am concerned about. I set up belays so that a Factor 2 is a VERY low probability. I always have the rope running through a piece above me, so a factor 1.9? is about as big as I will ever need to hold. If I am worried about a true factor 2 (which is virtually never), I will use a grigri. My concern is generating stopping power where the direction of pull is up.
An ATC XP, I don´t normally test against an ATC as it is somewhat outdated against the more modern plates though we still use it to establish the rope benchmark because there is a good deal of information about its performance and it´s still available in it´s original design which gives good continuity.
It´s Brian (and the UIAA) that refer to factor 2 falls, not me as Edelrid specifically exclude them from the remit for the MegaJul. That said a 1m factor 2 is a mild and uninteresting thing compared with a 30m factor 1.9 when it comes to the forces generated and energy that needs to be dissapated. The fall factor concept is something developed to easily explain to climbers the severity of a fall and not something we use generally as a working tool.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Brian wrote: +1 But I still can't believe that an ATC will hold a factor 2 fall easier than a assisted braking device. I sent Edelrid an email to see if they have any tests on factor 2 falls.
Edelrid nowhere say it is an assisted braking device, they say "High braking performance assists the belayer with leader falls" which is the case for all belay devices as they assist the belayer.
Guideline #1: Don't be a jerk.

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