Scheister TR and broken biner report


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Fremont, CA
Topic Author's Original Post - Oct 2, 2008 - 06:41pm PT
The Setup
Last Saturday, October 27th, my partner, Dave and I climbed Scheister on Sugarloaf near Lake Tahoe, CA. I had done this route almost exactly a year ago with Zander. The climb was going great until the alternative, stem finish which I had done twice before. From a large, fairly flat belay station, I climbed on top of some big blocks and clipped a bolt, which basically sits a foot or so above the edge of a wall that turns from vertical to fairly flat (maybe 20 or 30 degree slope). I used a 24 quickdraw with Mammut Moses carabiners on both sides and clipped the rope into the bottom biner. The bottom biner hangs over the edge by a few inches. From the blocks, I stemmed between two walls (pretty wide stem) and moved up until I could get my right foot high into a dish a little below and to the right of the bolt. I finished the move and then started to partially down climb the move to show Dave where to place his feet. I felt very secure with my hand on a knob and my right foot in the dish, but as I put my left foot against the back wall, I slipped.

The Event
My best guess is that it should have been a 3 or 4 foot fall on about 15 feet of rope. Before the fall, I was talking to Dave about foot position so he had me locked off and he was belaying me off of his harness, not directly off of the anchor. When the rope came taut, the carabiner attached to the bolt immediately broke in half. I dropped the rest of the way onto the slab near Dave. I landed on my feet and then slipped onto my rear. I came out of it relatively unharmed. I banged my wrist a little and had a cut that bled lightly to moderately and I bruised my butt and tailbone. A little shaken, we finished the climb via the 5.6 tunnel-through and walked off. Other than coming within one step of getting bit by a rattle snake, the walk out and drive home were uneventful.

The aftermath (so far)
I sent an email to customer support at Mammut and received a prompt response from their Hardware Product Manager. He expressed his concern and called for a UPS tag to pick up the broken carabiner so it could be shipped to Switzerland for testing. It is currently en route and we will have an answer when they have completed their testing. I will update as soon as I hear from them.

There are 10s of thousands of Mammut Moses carabiners out there. Please tell me there are a lot of people out there who have taken falls on these biners without them breaking. That would give me some measure of confidence. Anyone have a story?

Climb safe.


Mike Z


Trad climber
one of god's mountain temples....
Oct 2, 2008 - 06:44pm PT
Wow. Glad to hear about the safe outcome. Interested to hear the report on the biner as well...


Trad climber
Monrovia, California
Oct 2, 2008 - 07:23pm PT
Send the biner to Mammut for inspection. They are a reputable company.

That said, I took one look at those biners, and bought something else instead. Just a gut feeling. No science or testing behind it.

I love their ropes and use them almost exclusively, so I do not mean to diss the mammut.

Good news you got off more or less unscathed. Cheers for that!

edit: ok, I am a slow reader.... we'll be interested in the results.

Oct 2, 2008 - 07:26pm PT

A friends backyard with the neighbors wifi
Oct 2, 2008 - 07:29pm PT
A friend of mine broke the exact same carabiner not too long ago. Maybe 9 months.

He had protected in the back of a chimeny and when he fell the biner hit the edge of the chimeny (it was on a long sling) and the thing just snapped in half, exactly how yours did. I might have the photos around here somewhere.. Ill take a look.

Glad your ok


I cant get the image to come through. But it looks almost exactly like your broken carabiner. His broke with a tiny bit less of the corner on it. The back post doesnt hook at all.

Fremont, CA
Topic Author's Reply - Oct 2, 2008 - 07:59pm PT
I'm sure that Mammut would be very interested in seeing that. Does he still have it? If not, maybe you can read the lot number from your pictures. On the spine, just before the ratings (23 kN closed, 8 kN open, etc) there should be a 4 digit number. The one of mine that broke was lot number 0107.


Fremont, CA
Topic Author's Reply - Oct 3, 2008 - 01:31am PT


Oct 3, 2008 - 09:31am PT

Mike with the broken biner after finishing the route.
He probably fell 12 to 15 feet right onto the granite slab below me.

tom woods

Gym climber
Bishop, CA
Oct 3, 2008 - 10:53am PT
I've heard of biners breaking if they get knocked open during a fall. This biner was through a bolt? Yikes!


Trad climber
the south
Oct 3, 2008 - 11:27am PT
That sure looks like an open gate deal, but really in such a short fall, even open gate, those things are supposed to be good for from 7 to 9 kN.

I don't know which it is for those particular biners though.

You could roughly calculate the kN you generated with your mass in Kg and the distance fallen (up to the break) in meters. Supply your weight in pounds and the distance in feet and several people here could just convert and do it for you.

In your estimation, was it even possible for the gate to slap the wall and open in the fall?

The other thing is, could the biner have rotated up and gotten some weird torque from the hanger? This sound really unlikely since you had it on a two footer, but ya gotta wonder.

A break with the gate closed in your circumstances, barring a weird torque from the hanger would be REALLY scary.

Trad climber
Kalispell, Montanagonia
Oct 3, 2008 - 11:42am PT
Mike, not to worry. I own a couple dozen of these and I know for fact that I've fallen on one for three consecutive tries on a move. I am not a dainty sport rat either see pic. 260 lbs.

I fell many more times this year and they most ceartainly were in the system then also. Most of my "Aid Only" pieces are racked on them and because I solo almost exclusively I don't use a lot of slings so they get pulled on a lot and hard. Rest easy, they are good beiners, but there are tougher.
If my fat butt won't weasel one apart they can hold some pretty good heft, however with a little twist or levering anyone's beaner will open like butter.

climber's near nevada...
Oct 3, 2008 - 11:55am PT
"A friend of mine broke the exact same carabiner not too long ago."

did he send it in to mammut ?

Oct 3, 2008 - 12:18pm PT
'Glad you're O.K.

Punishment for hanging is usually more serious...

As noted above, with where the break is it appears that the gate was not totally shut. 'Better hope that's the case...


edit: the wire gate 'biners that do not have a 'hooded' gate as the BD Hotwire can be opened by merely brushing the rock. I believe that the hooded gate is the patent that BD holds for that product. 'Makes ya wonder why...

Fremont, CA
Topic Author's Reply - Oct 3, 2008 - 12:34pm PT
EC, not sure what you mean by punishment for hanging.

Fremont, CA
Topic Author's Reply - Oct 3, 2008 - 12:59pm PT
About the possibility of gate opening:

The location of the bolt is on a low angle slab above the difficult move. To clip, I had to reach out to the right so I'm pretty sure I had the gate to the left since that is most natural to me. Since the angle of the rock is low, the biner was resting partially on the side of the gate (see above comment about wiregate biners with something that protects them from the side, I think Helium biners have this). I was a little to the right of the draw when I fell so the load on the top biner in combination with the swing to the left could have opened the gate. I'll be paying more attention to the orientation of the top biner as well as the bottom biner in future climbs I'm sure.

About the force on the gear:

With gear, I'm 85 kg. My belayer is about the same, belaying from a standing position with a Guide ATC off his harness. Fall was about 3-4' on about 15' of rope (9.4 mm Beal Stinger). If someone can calculate the load on the biner from that, I'd be grateful. It is hard to estimate the time over which the impact on the biner occurred, but maybe there are some empirical charts out there that can help. Zander pointed me to some information in J. Long's anchors book that I haven't had a chance to look at yet. He thought that 2-4 kN seemed reasonable for this fall. The biner is rated 23 kN with gate closed, 8 kN with gate open, and 8 kN in the short direction.

Oct 3, 2008 - 01:13pm PT
My Bad, I misunderstood your account 'before the fall'.

Chris McNamara

SuperTopo staff member
Oct 3, 2008 - 01:19pm PT
scary. i had a non-wire gate biner break during a fall. I think it was because the "biner chatter" caused by the rope running through. it was then loaded when the gate was open. i think.

after that i favored wire gate biners because they have less biner chatter. but this forum topic/post potentially pokes a hole in that reasoning.

Oct 3, 2008 - 01:49pm PT
Scary, glad you are relatively unhurt. Curious to know what Mammut will say..

One small nit - you probably meant to say September 27 above.
Clint Cummins

Trad climber
SF Bay area, CA
Oct 3, 2008 - 01:58pm PT

Thanks for the detailed description.

Do you remember what kind of bolt hanger it was?

some common hanger types

Like Curt (dirtineye) suggested, maybe the biner got stuck in some orientation in the hanger and got torqued in an unusual load.

You said the gate was on the left side. Was the gate opening on the top or bottom? (It would be on the top if you clip the bolt and do not rotate the biner).

It sounds like this is how you were clipped (gate up and left).

I recall some biner breaking accident described on, where the biner got opened by the hanger. You could even get a situation where the notch on the nose of the biner is caught on the bottom of the hanger (with gate open on the other side of the hanger). That would probably be one of the weakest positions for the biner.

Notch loaded on hanger. It's hard to get the biner into this situation. It might happen if you were clipping desperately and not able to see it very well (probably not the case for you). But for some shapes of hangers and biners, it might happen on rotation of the biner during a fall?

Here is a link to other situations where biners have broken:
(Chris Harmston, "They all broke in open gate.")

Not there
Oct 3, 2008 - 02:18pm PT
I want to hear what Mammut can figure out from this. I too have a great love for their ropes.
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