No More Carabiner Grooves?

I lost several 'biners to deep rope grooves and started looking at buying rescue/professional hardware since it's all made of steel. I almost did it, but couldn't stomach the size/weight. Luckily edelrid makes a line of carabiners called "Bulletproof." Lightweight aluminum biners with a small steel plate on the rope-bearing surface. I've descended a couple thousand feet at this point using it and there is no rope groove At All. I've also noticed it stays significantly cooler even when rappelling quickly. This makes sense because steel has a MUCH lower thermal conductivity coefficient. So the heat generated by the rope doesn't spread to the rest of the device and instead stays right on the little steel plate. I have the screwgate belay carabiner in the bulletproof line and I checked and it is compatible for sure with a Critr and Pirana. I think everyone should use these things, especially on canyons where your rope gets real sandy. P.S. I swear I don't work for edelrid, these things have just eliminated my need to buy more carabiners indefinitely and I wanna spread the good news. They make 'em in every style and function to suite your fancy.

Just a note... Steel has a lower coefficient of friction than aluminum, and therefore LESS heat is generated across the carabiner when using a steel (implanted) carabiner. I suspect this has more to do with the carabiner not getting hot than the changes in thermal conductivity.

Tom

What Tom said.

Plus, Petzl tried this inlay feature with the Croll a few years back...mixed reviews from my crowd. Accomplished the wear advantage, yes. Created a razor sharp edge after major use wore away to the underlying aluminum. Cut you, it will. Looks like a good product/idea, but buyer beware.

[Edit] Not as much a rope cutting concern, unless you're using it in a bizarre way. It's more of a fillet danger for the fingers. Hopefully this new design is compensating for that.

I have been using the full steel HMS. It is pretty light vs other steel biners. The weight saved between it and these with the inserts is not really worth it to me. I would like to see what they look like after a lot of use then maybe I would switch.

Your comment got me worried about losing friction on rappel because both the carabiner and the ATC I use have steel plates on the rope surfaces. I found an arborist site comparing friction differences between rope over steel and aluminum rings. I condensed one of their tables and found percent difference to get this:

Some of the ropes they tested were only tested with steel and "polished aluminum" instead of just normal aluminum. The values highlighted in orange are likely the ones we care about, those were the values comparing normal steel to normal aluminum. Sources of error for this would be that these are rings and not carabiners, and that these were gigantic arborist ropes of 11mm or larger. I think the Capstan equation is what governs this type of friction and it doesn't seem like rope diameter would play too much of a role. The differences in friction between Aluminum and Steel seem to be on the small/negligible side. Do you think the difference between the two of them would grow larger as rope diameter decreases? Do these percent differences seem large enough to make a difference in the heat flow across the biner?
Source: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=2ahUKEwi5gsCP6szdAhWFLnwKHf1QC5YQFjAGegQICBAC&url=http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=2976&Type=2&usg=AOvVaw0k9evMv1UUdXcKG_kXmWwj

Nice!

A much less difference that it feels like in the field...

Whatever aluminum device you use, after slight use, every surface the rope runs across is polished.

There are small differences in the coefficient of friction based on pressure, so larger ropes would likely have less pressure, maybe less friction. Again, a small difference.

Tom

Well that's awesome then, steel had More friction than polished aluminum in every test (albeit in the hundredths place, so like you said, a tiny difference.) So it seems that steel vs polished aluminum is about even as far as friction goes.

ATC's do not have steel running surfaces. Perhaps you are using an ATC-CLONE? Which Clone are you using?

Tom

Yes I should have specified, it's an ATC style (I should probably be calling it a tube-style) device. I use the "Mammut Bionic Alpine Belay" device. It has a slightly larger rope diameter range than the petzl reverso I was using, and it has steel on the rope surfaces so it stays cool and seems to have almost no wear on it whatsoever even after several thousand feet of (sometimes very sandy) canyon descent.

Dunno. I've tried a steel biner a few times. Very perceptible loss in friction.

For the money, 12 bucks for an Attache (or less used at a swap) versus 25 for the similar model in steel? I'd probably just replace the grooved ones.

Had an opportunity to buy an ATC made out of Titanium. Wish I woulda. Light weight. Custom BD (not a clone). Hmmm.

Someone with a modicum of machining talent could make a slotted device ala ATC out of tool steel.... More "hmmm.".

Out of curiosity how much was the titanium ATC? I know Conterra makes a titanium rap device called the scarab but it's stupid expensive since Titanium is such a nightmare to machine.

The main problem with the Petzl Croll SS wear plate: a void between the plate and the aluminum body of the Croll. Once the plate wears through, a sharp-edged hole is formed, which can cut rope (and other things). I imagine Edelrid was well aware of this issue when developing their carabiners. AFAIK Petzl has since addressed this issue with a wear indicator built into the Croll.

Prior 'bulletproof' discussion: http://canyoncollective.com/threads/edelrid-bulletproof-carabiner.25097/

More on the Petzl Croll issue:

https://www.facebook.com/groups/2205123638/permalink/10153734872323639/
https://www.petzl.com/US/en/Sport/N...a-CROLL-ascender-is-worn-out-(caving-context)

Was never available...prototype only. Was 20$ and I shouldna passed on it.

Well dang hank, guess I shoulda searched and seen your thread before posting mine! ;P Can report I've been using one as my descender connector for a little while now and also pretty frequent gym and outdoor climbing. It's holding up pretty well so far but I'm nowhere close to the usage frequency you Utah natives seem to be able to rack up.

Oooooh, that hurts to hear!

Tables and test data are one thing. Real world experience may be more telling than cold numbers. Not exactly sure what 3.636363% difference feels and acts like on a 400' rappel. I guess I'm not skilled in that way.

I've used stainless steel descending devices far more than aluminum over the past....well let's just say a long time. Trust me, SS is faster. This included biners...and noticeably faster when polished.

Out of control faster? No, never. Because it's all relative and variable depending on the application, device, rope, environment... you name it. You grow accustom and adjust to what you have, and know.... or you die (sensationalism, yes, but it's a fact).

YMMV?? Although, if it does by a significant amount I might would be interested in a deep dive discussion of metallurgy, otherwise I will yield to pragmatism.

Thanks for the report - sounds positive. Please report back with photos when the steel wears through? A few trips through Spry Canyon (ZION) in damp conditions with poor rope care (i.e. not keeping it clean) ought to do it.

Having used SS and AL versions of the exact same device, I can say the friction difference is quite obvious.

Last comment regarding the arborist data above, confessing that my previous post was more a knee-jerk reaction. Honestly had no idea what a "cambium saver ring" was or how it is used. Youtube educated me (and now that makes me an expert, I suppose). Cool device for the tree climber, a retrievable anchor, of sorts...and I suppose less "bark in the eye" when deploying rope.

After reading the article, and understanding roughly 1/2 of what I read, not because of the math so much as knowing the application - being only a novice tree climber circa 1960 (ie. how and why an arborist does what they do).

My revised conclusion from their findings is that we are probably not accounting for many of the peculiarities of the application and methods. In other words, it's not an apple to apple comparison. The angle of the rope/device configuration, rope diameters cited (11mm-13mm), and methods not as applicable to a carabiner in a descending device and/or descending device material and configuration particularities in general.

I will give them this though, they were thorough with their test case.

Next topic, the intrinsic properties of titanium vs soapstone rings....and when we finish that, just exactly what is a Goove?

I use a steel HMS biner from Liberty Mountain. Yeah, it’s heavy for a carabiner but I’m happy to carry the extra weight for a carabiner that lasts legitimately 10 times longer, does not have the potential rope shredding hazard, and only costs ~$18. Plus the heavy brass barrel on the screw lock is really nice, in a tactile way, and it doesn’t jam up with sand nearly as badly as aluminum barrels.

This is no hyperbole or exaggeration. I’ve literally used up aluminum carabiners by the canyon. The $$$ adds up. I do an honest 40-70 canyons every year and have gotten 12-18 months out of my steelies. I bought 3 of them in the fall of 2015 and I’m just about to retire number 2.

The fancy steel insert on the Edelrid seems like a good idea on the surface, but you get what, 1/16” of consumable wear? Then you find out the hard way that your biner has just gone out of service as you feel an odd sensation that you discover to be shredding rope 150’ down a 300’ rappel. Not likely to instantly sever the rope, but it certainly makes your long, expensive rope age prematurely at the very least.

I’ve passed a core shot (caused by someone else’s ATC) 150’ off the deck on a free-hanging rappel. One and done for me, thanks.


Even if the interface between the steel and aluminum in the Edelrid is free of any gap, the materials will wear differentially and at the very least, the steel will form an overly acute surface radius. No need to subject a rope/your safety to that kind of wear/risk. Maybe you get through half of Heaps before you figure out why your ropes seem to be getting fuzzy at a peculiarly fast rate. Damage done. Oops


As I said, I’ll happily carry the extra weight and use that steel biner till half of it is worn through and still have the piece of mind that it’s still stronger than any aluminum carabiner and won’t become a rope shredding hazard at the most inconvenient instant.

The gimmick isn’t worth the weight savings or the money, at least in canyoneering.

My $.02

From Anthony Dye on FB:

https://www.facebook.com/groups/1589401311365080/permalink/1912169239088284/

Hey friends!

I went on a 5 day trip not too long ago. Long days with wet and sandy conditions. On day 3 I noticed my almost new carabiner was worn nearly 2/3 through!

I think I hadn't noticed it partially because of my critr, and partially because when I hook onto the rope, the biner gate is facing me, so that wear point of the carabiner isn't conveniently visible.

A good reminder to check your metal gear and not only your fabric gear, especially aluminum. And to check your gear each day, or even each rappel, rather than just between trips... be safe out there!