Nose hooking Mammut Moses

I've recently learned to lead trad, and have been building a rack. I started out buying Mammut Classic wire gate biners, but started to buy Moses to save a bit of weight.

I read somewhere that they had a tendency to nose-hook, so I did a few tests myself to see what would happen. As I said, I'm fairly new at trad climbing, so I'm not sure if my tests mimic real-world situations, or would ever repeat outside.

First test: I took two dynema shoulder slings and attached them to the biner. Then, I hung the biner from the slings, ie one sling in each hand, biner hanging in front of me. I then pulled my hands apart. A significant number of times, the sling hooked on the nose of the biner. What I think happened was that the sling ran along the top of the biner and instead of running smoothly down the biner and along the gate, it got hung up on the nose. I repeated the test with a slightly wider sling - the Mammut tubular sling - and got similar results.

Second test: I hung a dyneema sling from a door frame, then ran a 7mil cord through it (didn't have my climbing rope handy) and ran it through the biner as if I were clipping a piece of protection. With a little jiggling I was able to get the biner sideways, and when I pulled the rope down to simulate a fall, it hooked the nose a few times, sometimes on the sling and sometimes the rope.

So my questions:
-are my tests valid or am I simulating conditions that are not reproducable in the real world?
-would results be different with 9mm or 10mm rope? I'd guess they would be, as a larger rope would be less likely to get stuck, but there still remains the chance that the sling might get caught?
-should I be worried about this?

As you've noticed, the Moses is imbalanced and tend to flip (sort of like my ex-Girlfriend); it is notorious for that. In general, the rope getting caught on the nose is not a concern. Of greater concern is when the biner flips around and the nose gets hung up on a sling or on a stopper wire, leading to either cross loading or simply loading away from the spine (both weaken the biner).

A few points/questions to address:

Is this a safety concern that you should be worried about?.... I don't know. Breaking a biner is still pretty unlikely, even in the scenarios shown above, but chronically crossloaded biners are not ideal either. Hopefully someone else will chime in on this.

What can you do?.... First, stop buying these biners. They are a poor design; there are plenty of other options that are lighter, handle better, and don't tend to flip/snag. With the ones you have, one option is to use tape or keeper bands to keep them from flipping on the slings (but this has serious safety concerns related to it too... ukclimbing.com/news/item.ph…). With the few Moses biners that I have, I've moved them off of open sling alpine draws and put them onto regular dogbone quickdraws where they are held tight by the dogbone and don't flip.

I had one crossload on a fall last April. I've since switched out the gear biner for all of my draws to the hooded Oz.

Full story here

Glass Tupperware wrote:I had one crossload on a fall last April. I've since switched out the gear biner for all of my draws to the hooded Oz. Full story here

Looking at your report there...what exactly went wrong with that piece WRT the crossloading that caused failure. It doesn't look like the biner or the sling broke. Did the biner come unclipped from something?

JCM wrote: Looking at your report there...what exactly went wrong with that piece WRT the crossloading that caused failure. It doesn't look like the biner or the sling broke. Did the biner come unclipped from something?

I believe that the jingling of my rope (from climbing above the placement) oriented the sling and the wire from my nut in such a way that the the wire was hooked on the gate (perhaps cradled around the outer part of the nose).

Perhaps something like this. Maybe it could have happened with any biner.

Thanks, everyone, for the replies

Glass Tupperware wrote:Full story here

Indeed - that was the post that got me thinking about the Moses biners.

I'm going to put them on the rope end of some quickdraws and see how easy they are to clip as JCM has recommended.

Not to be a critic, but have you tried replicating your experiment with other wiregate biners?

jonathan.lipkin wrote: I'm going to put them on the rope end of some quickdraws and see how easy they are to clip as JCM has recommended.

They actually kind of suck as biners to use on quickdraws (too small, not the easiest clip), but they are even worse for any other use (flip-over and crossload danger). Just kind of an inferior product design, which is disappointing from a company that does a great job at most things.

John Peters wrote:Not to be a critic, but have you tried replicating your experiment with other wiregate biners?

Hey, John. Not a bad question at all. I just spent four hours at the gym. If I can drag myself out of bed, I'll give it a try later tonight. You are correct, though, it would be a better test if I had tested other carabiners in similar conditions.

BYW, when I tried two moses carabiners opposed, they did not hook.

I stopped using the Moses after I had 2 cases where my second told me that the nose had hooked, in both cases on a stopper wire. I never fell on one with the nose hooked.

I didn't fully understand why this happened until I read the Glass Tupperware story and then I tried to recreate it. I found it is easy to do with the Moses, and with another Mammut carabiner that has an even deeper notch on the nose than the Moses. I also played around with Wild Country astro's and the old OZ without the hoodwire. I can get a stopper wire to catch a little on the old OZ but it's not nearly as easy as the 2 Mammuts.

Here is a picture of the carabiner that was the worst. You can see how deep and flat the notch on the nose is. I don't know if they sell these anymore but it's probably closest to the Mammut Classic wire.

Compare that troublesome Mammut to a CAMP Photon. I can't see a difference re. the notch. (Not saying the Photon is OK (never used 'em), only that the Mammut design isn't that unique.)

Tried with a few others:
-Mammut Classic
-Camp Photon
-BD Hotwire wiregate and solid gate

Results were pretty much the same, surprisingly. Nose hooking occurred pretty frequently, about 50% of the time. More often with dynema than the tubular Mammut slings, probably because of the width.

My guess is that my test does not reflect real-world climbing conditions, otherwise we'd hear a lot more about broken carabiners.

I have a dozen 10cm Moses quick draws that I have been using for sport climbing for the last two seasons without issue.
They are nice and light and I find them easy to handle and clip. I see how they could have a tendency to nose hook but at least in my case it has not proven to be an issue.