DMM THOR biner

Paul-B wrote: . your rope would break looong before that. Most are rated to 8-10kN, right?

Wrong. Maximum impact force rating is 8-10kN on most single ropes, not breaking strength.

But, it is not the closed gate rating on this biner that is impressive. It is the open gate biner rating that is. And there have been several open gate biners that have failed over the years. I'm suggesting anyone needs to replace their current biners with this one. But, if you are in the market for some new biners, it is worth considering.

DrApnea wrote:Though I don't really care about what the numbers say, I have had fatigued gear fail at much less than the rated strength (wire break off of an HB brass at the brass/wire interface during a soft bounce test).

A broken nut as a result of cable fraying is not fatigue (in a technical, metallurgy sense), that is damage. Metal fatigue refers to the condition that occurs after cyclic loading by which microcracks propagate through the material laterally until it fails.

Paul-B wrote: Most are rated to 8-10kN, right?

No. And ropes are not rated for breaking strength. Zero manufacturers publish official breaking strength info on dynamic ropes. But to answer your question, a brand new dynamic rope, when clipped to a carabiner in a manner analgous of a person leading a route, coudl hold more than 24kN because the load is halved among two strands. One strand of dynamic rope is not likely to hold 24kN, but two could (depends on the rope).

Paul-B wrote: I agree with most of what you say. As i said before, I would care much more about fatigue strength than adding a few kN to the impact force. However, these are not necessarily correlated. It may be in making it stronger for a single fall it fatigues more quickly.

You are correct, the strength rating and fatigue strengths are not necessarily linked. Surface area, surface preparation and shape are more critical to the fatigue strength. However, for a typical climbing scenario, fatigue strength is meaningless. You would literally cut through a carabiner from rope abrasion before the carabiner would fail from fatigue from too many falls.

However, fatigue is plausible in some scenarios. I have seen a pulley fail from fatigue when it was permanently used in a slackline setup. But for climbing applications, fatigue is not a concern. MIT did a study on this awhile back which I can post (or just Google it).

Matt N wrote:If there were evidence that a 'stronger' biner had a better chance of surviving a nose-hooked bolt or rock-edge loading fall, then that would be pretty good info and a reason to buy needlessly strong biners. Anyone have a clue how this would play out? Doubt there's any testing on these situations as they could be a bit hard to replicate.

I have nose hooked biners in my pull tester. I have never tested them in a closed gate scenario, but in an open gate scenario, biners rated for 7kN open-gate were failing at just over 2kN when nose hooked.

20 kN wrote: by which microcracks propagate

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!
MICROCRACKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Not going to get into an argument on this but I'm sure you are right in correcting my terminology. The cable however did pass visual inspection without any of the wire's strands appearing broken prior to use, so again, if it were built stronger, perhaps it wouldn't have failed with a low impact force. Same thing applies to all gear.
This is why I only climb with opposite and opposed steel carabiners now on each end of my doubled up sport draws.

D.Buffum wrote: No. Your ropes maximum impact rating is usually in that range. Ropes are waaay stronger than that. You'll never break a rope unless it's been damaged somehow.

Thanks, I guess I was misunderstanding that rating. I was not trying to be argumentative or "troll" as the OP suggested. My point still stands that this is still one of the strongest pieces in the chain, strengthening the closed strong axis doesn't change much. Open rating is probably worthwhile, although as others have pointed out this doesn't mean a stronger biner if nose hooked.

John Wilder wrote: The strong axis strength isnt important, although it can be an indicator of the strengths that are- open gate and minor axis.

Just going to say one last thing on this and leave it at that.

blackdiamondequipment.com/e…

Hooked nose biners break at roughly 10% of Closed gate strength. Closed gate strength is important. A 28kn Thor would give you a better margin than a 20Kn Oz. And that is just talking nose hooked scenarios of closed gate failure. There are others.

Anyhow, wicked strong biner in closed and open gate. Kudos to dmm and looking forward to even stronger biners in the future!

Pete Spri wrote: Just going to say one last thing on this and leave it at that. h.ttp://blackdiamondequipment.com/en/qc-lab-weakness-of-nosehooked-carabinershtml Hooked nose biners break at roughly 10% of Closed gate strength. Closed gate strength is important. A 28kn Thor would give you a better margin than a 20Kn Oz. And that is just talking nose hooked scenarios of closed gate failure. There are others. Anyhow, wicked strong biner in closed and open gate. Kudos to dmm and looking forward to even stronger biners in the future!

there is no evidence that a THOR will give you a better nose hooked breaking strength than any other biner ...

the BD document says

When a carabiner is loaded while the nose is hung-up on a bolt hanger, a leveraging open-gate scenario occurs. Carabiners are significantly weaker in this configuration—less than 10% of closed-gate strength.


it doesnt say that a 28 kn closed gate biner will break nosed hook at a substantially higher load than say a 22 kn one ...

we simply dont know until someone does an actual test

just because a biner is stronger in one configuration, doesnt mean its also stronger in another ... case in point the THOR is still rated at 7 KN xloaded ... the same as many other "weaker" biners

its quite interesting that DMM is going with "stonger" biners rather than lighter one .... and interesting that they are going back to notched from the notchless on the SHIELD

DMM makes quality kit ... but all this talk about "safety" is funny as it seems that even within their own line, there "safer" and "less safe" biners when one compares the features they promote

and yes i do own and use much DMM gear

;)

mostly I'm just excited to have a new "all rounder" biner

bearbreeder wrote:and interesting that they are going back to notched from the notchless on the SHIELD

Perhaps they want to sell more biners that don't use licensed technology?

That would be a nice 'biner if it didn't have the hooked nose of death on it.