That "pear-shaped" carabiner is actually an "offset-D" carabiner which is designed to be loaded along the axis of the back bar. If you actually used a pear shaped carabiner, which incidentally is pear shaped and ,like a pear, is symetrical in design, you would find that the breaking force for the tri-loading would be significantly higher. Obviously, if you tri-load an offset-D carabiner there is an undue amount of force along the axis of the gate, which it was never designed to accommodate.
it should in theory load more down the spine of the crab and therefore be closer to the rated strength, always good to see a physical science approach to climbing/slacklining gear though!
I have been thinking about a way to solve this problem for a while now in climbing anchors and i think i may have come up with something. Join the two ends of the webbing with a butterfly bend, no crossloading of the biner and the knot is known for being strong on all sides.
Hey :) i'm watching your videos for 2 years now and really enjoy them all. Keep up your nice work! ;) A few weeks ago i bought my first 100m Slackline and i wanted to know if it is possible to connect 2 roundslings with an anchor sting or another knot, if the roundsling is too short for a tree... I did it today... but i wasn't really sure if its save enough. Greetings from Germany :)
Hi, it is no problem to connect to round slings with a girth hitch (=Ankerstich). There is a slight reduction in breaking strength. But e.g. with purple slings that have a working load limit of 1 ton, the breaking strength is 7 tons due to the safety factor. So the strength of those slings is mostly much higher than needed in the slackline world. You mostly have to be careful that there is no abrasion happening on the slings.
They are for two medium weight pulley set ups. They are steel and no 45 degree type loading as in your video. I always use gear that is stronger than the job needs. An architect once told me that when he builds a balcony he builds it for 50 people because one day he says the queen will be passing in a parade and there will be 50 people on that balcony watching.
When the gate breaks the load dramatically decreases. The only reason there are no parts flying around is it's only short slings which are slowly pulled by a hydraulic cylinder. THERE IS NO % MORE LOAD AFTER FAILURE. Any real life load at that biner could not be stopped by it after the gate is broken, except for the rare case the static load is below the load the biner is rated with open gate and the gate by a short and precisely dosed short impact.
Someone read the manual that says if combining multiple anchor points combine them to the small end to eliminate Cross loading 🤦♂️ I am glad to finally be able to say some numbers when people insist on doing this wrong.... Don't like that it's still 23kN
I agree with tdeglers. That is an asymmetrical d-shaped carabiner that also happens to be pear shaped. Looks a lot like this: www.omniprogear.com/OPG-Steel-BiLock-D-Carabiner-p/opg_cdtl.htm
Definitely should never tri load your carabiners, if possible. But also I wanted to point out that your test is flawed. Your testing the 2 biners unequally. The oval shaped one you use a webbing sling for most of the testing. Vs. The pear shaped you use a those steel links. That's why you see the breaking point significantly weaker. The webbing sling spreads out the load on the multiple points of contact. Think of how a girth hitch vs. Basket hitch does the same thing.
Your ovals were all "upside down", the pear shaped was only "upside down" for the very last take. Youre creating conclusions which don't exist. What you actually showed: pear upside down: 45Kn pear full: 55Kn oval upside down: 30Kn oval straight: 30Kn Extra result: pear other way up: 30Kn...
"Upside down" means that two slings are connected on the smaller side of the Pear (Type H or HMS). Oval (type X) is symmetrical and has no smaller side. Tests are conclusive. With load on the larger side HMS (55º) 23kN. Conclusions are the following: 1. HMS are very good for straight load. 2. HMS is weakened by pre-load and angle. You may have bad surprises when using inadequately. 3. Oval resistance is consistent even with pre-load and angle. Take care
Well well it's 2020 it's still a valuable information thank you
Thanks a lot for the great video! I am sure it will significantly help our community to slack safer! ;)
That is SO unexpected. My understanding was that the pear carabiner was designed for tri-load in the way you had it set up in the first tests.
Can you please perform the same or similar tests using stainless steel or aluminum carabiners?
Thanks guys! It helps a lot.
Did not see that coming! Very interesting.
Very professional and convincing. Thank you for the video :)
That "pear-shaped" carabiner is actually an "offset-D" carabiner which is designed to be loaded along the axis of the back bar. If you actually used a pear shaped carabiner, which incidentally is pear shaped and ,like a pear, is symetrical in design, you would find that the breaking force for the tri-loading would be significantly higher. Obviously, if you tri-load an offset-D carabiner there is an undue amount of force along the axis of the gate, which it was never designed to accommodate.
Brazil: Obrigado por compartilhar!
Watching this in 2021 before taking my climbing/abseiling/high ropes guiding exam
would be interesting to see the test repeated with the large end of the HMS pointing at the wider side of the rigging, as it is designed for?
it should in theory load more down the spine of the crab and therefore be closer to the rated strength, always good to see a physical science approach to climbing/slacklining gear though!
I have been thinking about a way to solve this problem for a while now in climbing anchors and i think i may have come up with something. Join the two ends of the webbing with a butterfly bend, no crossloading of the biner and the knot is known for being strong on all sides.
Thanks for the valuable information!
Hey :) i'm watching your videos for 2 years now and really enjoy them all. Keep up your nice work! ;)
A few weeks ago i bought my first 100m Slackline and i wanted to know if it is possible to connect 2 roundslings with an anchor sting or another knot, if the roundsling is too short for a tree...
I did it today... but i wasn't really sure if its save enough.
Greetings from Germany :)
Hi, it is no problem to connect to round slings with a girth hitch (=Ankerstich). There is a slight reduction in breaking strength. But e.g. with purple slings that have a working load limit of 1 ton, the breaking strength is 7 tons due to the safety factor. So the strength of those slings is mostly much higher than needed in the slackline world. You mostly have to be careful that there is no abrasion happening on the slings.
ok :) thanks for the fast reply! :)
pura vida slackline😎👍
Thanks for sharing!
What about a small rigging plate for load distribution? Like a Petzl Paw S?
That'd make a ton of sense in my mind
is that stuff "not common" in the slacking community?
Is the weakening of the carabiners after repetitive loading really so big of an issue with steel biners?
Is there any reason why you can't use a girth hitch to avoid the 45 degree angle when tri loading?
No.... we do this, but with rapelling, where loads are significant lower. I also use fairly long slings to reduce the angle....
Great. I just bought 10 ovals on Amazon this morning at a good price. It was a choice between 5 pear or 10 oval with a few dollars difference.
Good choice. I just hope the quality is the same as the biners we've tested. Not all oval biners will perform as good as these ones...
They are for two medium weight pulley set ups. They are steel and no 45 degree type loading as in your video. I always use gear that is stronger than the job needs. An architect once told me that when he builds a balcony he builds it for 50 people because one day he says the queen will be passing in a parade and there will be 50 people on that balcony watching.
In the market, there are available carabiner designed to work loaded in three directions.
I would question the shape decision of the pear=shape carabiner if the oval one is basically stronger.
Even though the gate broke it was still holding load... how % more load until absolute failure? Loading biener in correct orientation.
When the gate breaks the load dramatically decreases. The only reason there are no parts flying around is it's only short slings which are slowly pulled by a hydraulic cylinder. THERE IS NO % MORE LOAD AFTER FAILURE. Any real life load at that biner could not be stopped by it after the gate is broken, except for the rare case the static load is below the load the biner is rated with open gate and the gate by a short and precisely dosed short impact.
...or just don't tri-load your carabiners. Pretty easy to avoid.
thanks
I see petzl give a "warning" about that, why? what a point....
Just use two biners, one for each end of the sling, clip them into a welded ring, then another biner into the ring.....
thank you so muuuch
2019-3-29 首次阅览
拍得很好，继续加油
I love oval shapes
Someone read the manual that says if combining multiple anchor points combine them to the small end to eliminate Cross loading 🤦♂️
I am glad to finally be able to say some numbers when people insist on doing this wrong.... Don't like that it's still 23kN
very good~~
As a conclusion I would say the pear shaped one is always stronger. You just have to use it upside down.
well it is rated for 50 but still breaks at 45 even "upside down" so no, it is always weaker.
очень полезно! пасибо большое!!
This is good data
Is that D carabiner, not pear?
Unpredictable outcome
Thats why my roadeavour has a shape like that.
mind blow
Carabiner in your vid is d-shaped, not pear shaped. Pear shaped are basically hms. Easy to check. Otherwise great job man! :-)
no it is pear shaped... with a D shaped one, the back and the gate are still parallel...
I agree with tdeglers. That is an asymmetrical d-shaped carabiner that also happens to be pear shaped. Looks a lot like this:
www.omniprogear.com/OPG-Steel-BiLock-D-Carabiner-p/opg_cdtl.htm
you mean shape i think. i think theres a translation error.
If you divide the wide side, it will be weak.
You should continue the test all the way until the rope actually detaches. The pear shaped carabiner was still holding on when you aborted.
Definitely should never tri load your carabiners, if possible. But also I wanted to point out that your test is flawed. Your testing the 2 biners unequally. The oval shaped one you use a webbing sling for most of the testing. Vs. The pear shaped you use a those steel links. That's why you see the breaking point significantly weaker. The webbing sling spreads out the load on the multiple points of contact. Think of how a girth hitch vs. Basket hitch does the same thing.
Your ovals were all "upside down", the pear shaped was only "upside down" for the very last take. Youre creating conclusions which don't exist.
What you actually showed:
pear upside down: 45Kn
pear full: 55Kn
oval upside down: 30Kn
oval straight: 30Kn
Extra result: pear other way up: 30Kn...
"Upside down" means that two slings are connected on the smaller side of the Pear (Type H or HMS). Oval (type X) is symmetrical and has no smaller side. Tests are conclusive. With load on the larger side HMS (55º) 23kN. Conclusions are the following: 1. HMS are very good for straight load. 2. HMS is weakened by pre-load and angle. You may have bad surprises when using inadequately. 3. Oval resistance is consistent even with pre-load and angle. Take care
Thanks for sharing!