Guide Mode Belay set-up change? Edelrid thinks so

I'm sure 99% of you set up your guide mode belay the same way that I always have, but apparently according to Edelrid (they talk about the MegaJul as well as the BD ATC) there is the risk of the rope inverting within the device when belaying a follower with a single rope. I see little chance of the rope inverting because I never multi-pitch climb with a rope anything near 8mm, but perhaps the risk is the rope becoming stuck side-by side with itself. They now recommend setting up as described in the video.

youtube.com/watch?v=385cP_F…

They argue that the brake carabiner should also be clipped inside the thumb loop. Realizing that the risk here generally only involves the use of a skinny rope, is there a reason to change the way I've always done this or is it much ado about nothing?

Interesting because I hadn't heard this before

Interesting. I've always clipped the brake carabiner back around the climbers strand when belaying from above with a plate-style device (ala Kong GiGi) for this reason. The larger apature on the plate device makes it pretty easy to see the effect but I had never thought about for a tube-style device. Makes sense now that I see it.

Perhaps the next question is, in the event that you forget to flip the carabiner, what is the likelihood that your ATC-Guide is going to invert on you? I'm not suggesting that flipping the carabiner is irrelevant, rather I'm wondering whether we've all been playing with fire forever or if it's one of those practices that does add a margin of safety but adds it to a practice that's already very safe.

A deeper tube will resist this better than a shallower one, which is why the MegaJul and Kong GiGi are more prone to this. The instructions for the ATC Guide don't say to do this:

(though they do, hilariously, advise against using it as a tri-cam):


In the case of the MegaJul, I would use it how the manufacturer recommends.

If you're using a Reverso/ATC guide with a super skinny single rope (the thinnest currently available is the 8.5mm Beal Opera) this method probably a good idea as well. For normal singles, I wouldn't worry about it. And for doubles, it's a non-issue.

ETA: Some other things to consider: The MegaJul does not have the v-groove that the ATC Guide and Reverso 3/4 have. The V-groove makes it harder for the ropes to end up side-by-side, like the could in the rounded MegaJul or GiGi. Having the brake strand in the correct orientation (parallel to climber strand) will help prevent this (note that in the video, he has to pull the ATC Guide brake strand sideways to facilitate it flipping).

Edit 2: Just noticed that the ATC Guide also specifies a minimum size of 9mm for single ropes (7.7 for double/twin). Reverso 4 has a minimum size of 8.9mm for single, and 7.5mm for double/twin.

There was a discussion either her or on RC.com some years ago about this (related to an idiot recommending using guide mode for lead soloing) where I tested a number of devices and ropes to see at which load the rope flips and either jams solid or completely changes sides and releases. How the karabiner is clipped makes no real difference.
Nice that Edelrid have finally admitted guide mode isn´t perfect!

Following up on Jim's comment, I'd be curious to know at what force theory becomes reality. Would this happen in a factor 0.5 fall?

This has been known for many years.

The original thread was back in 2010 where a guide training clients reported:-
"We commonly use self-locking belay devices for ascending ropes. During some crevasse rescue training today we had a Reverso 3 fail to self-lock, as the weighted side squeezed past the break end to where it looked like it was loaded incorrectly. This happened twice - luckily with no injury. The rope being used was an 8.4 Sterling.
Has anyone encountered such a problem?"

The reply I gave then was:-
"I did some pull tests on guide plates (related to using them for roped-soloing):-

When you overload guide plates they do funny things.
The first is that the trapped rope escapes sideways from under the tensioned rope and gets trapped between the tensioned rope and the side of the slot.This is very difficult to free off and you have to dismantle everything and twist the locking krab brutally to release the rope.
Apply yet more load and the trapped rope where it crosses the tensioned rope goes down through the slot with a bang. At this point the holding power drops off considerably but not catastrophically, though pretty near!
Easy to releasse, just unclip the krab when unweighted.

ATC Guide. 8.2mm Edelrid, new,treated. First fail mode 2.05kN. Max fail load 4.06kN. Residual load 1.2kN
ATC Guide. 9mm Edelrid, used, non treated. First fail mode 2.96kN. Max fail load 5.58kN. Residual load 1.6kN

Reverso³. 8.2mm Edelrid, new,treated. First fail mode 1.6kN. Max fail load 2.38kN. Residual load 0.7kN
Reverso³. 9mm Edelrid, used, non treated. First fail mode 2.25kN. Max fail load 3.60kN. Residual load 0.9kN
Reverso³. 10.2 Mammut, used, non treated. First fail mode 3.68kN. Stopped test at 7kN as I didn´t have the tester guards on and things start breaking over these sort of loads!
All with Petzl Attache 12mm round profile karabiner.

I´ve some more results somewhere but can´t lay my hands on them at the moment, anyway I guess the picture is clear enough!"

If the weather is crap over the weekend I might try a few newer plates out of curiosity, I´m not that curious though really! The reason I initially tested was due to hitting the ground when the ATC guide I was testing failed to hold my weight as I moved around on the end of the rope.

Jim, what was your setup for the tests and for the instance where it failed on you? It seems that for self-belaying or ascending, the brake strand would not be parallel to the weighted strand. This would make it easier for the strands to bind or flip, since the brake (trapped) strand could have a sideways load on it.

I'm curious, b/c the original post was about top-belaying in guide mode, which I hadn't considered an issue before (I wouldn't consider using them for soloing or ascending).

steverett wrote:Jim, what was your setup for the tests and for the instance where it failed on you? It seems that for self-belaying or ascending, the brake strand would not be parallel to the weighted strand. This would make it easier for the strands to bind or flip, since the brake (trapped) strand could have a sideways load on it. I'm curious, b/c the original post was about top-belaying in guide mode, which I hadn't considered an issue before (I wouldn't consider using them for soloing or ascending).

Set up as for belaying on a top anchor, both strands hanging down.