I got my initial trad training in France in the early 80s and stopped & re-started trad leading over the years as I moved around (England, W. & E.Canada). For the latest re-start, I decided to read up on the current "gospel"and bought Long&Gaines’ climbing anchors on the recommendation of Colin (niloc on the forum).

This made me realize that, for years, I’ve been doing the sliding X differently than what seems to be the commonly accepted manner (which is to make a single 180deg twist in the middle of a single one of the two strands of the sling and clipping both the straight and twisted strands together). For my part, I twist both strands before clipping them, making sure that I twist them both with the same clockwise (or counter-clockwise) turn. The latter point is vital since, if they are twisted in opposite directions, a failure of one of the two points could let the whole thing unravel.

Reading the book has also led me to think about and hunt for answers on 3-piece self-equalized, low-extension, redundant anchors on this forum & on ST.com but I will leave that for another post. In going through these monster threads on equalizing anchors, I have come across references to something variously referred to as "Craig’s short" or "sliding W" for equalizing 3 placements that is done with two twists but did not come across something like my two-arm "sliding double-X". Searches on various likely keyword combinations (forums & Google) did not turn up anything else either. As a newcomer to this forum trying to catch up on many lengthy discussions going back several years, covering a wide variety of related topics and, most of the time, with key photos no longer available, I may well have missed relevant references and apologize if this has already been covered before.

When I tried the regular sliding X after coming across its first illustration in the book, I thought that my system might actually have some advantages because, even though it introduces 2 twists instead of 1, it forces the crossings of the tape or cord to remain above the central locker and to slide through it side-by-side and in the same direction (and also because it uses up the exact same length of tape or cord on each strand, which could be useful when the strands are tied together with limiting knots).

In the regular configuration, the one twist places the crossing of the strand above the biner initially. However, by making just a half-turn around its main axis, the biner tends to end up in a more balanced and symmetrical position with the strands crossing on the inside of the biner (ie right under the"basket" bar of the biner, assuming you clipped it right side up). In the book, the "clutch effect" was blamed for a) limiting the dynamic equalization under load between two unequal arms of the sliding X, on average and b) occasionally causing much larger differences in the equalization. I would have liked to see a more detailed dissection of this effect in the book or the forum since it seems that different things might happen with the regular sliding X that could play a role in this:

1. If the biner is not allowed to make the half-turn and the crossing of the twisted strand is kept above the biner, the twist on only one strand means that when the strands slide through the biner, they run in opposite directions.
1a. If they run side by side (more likely with cord), the friction they would generate would be relatively small, but
1b. if they run one on top of the other (more likely with tape), with the straight strand jamming the twisted one against the underside of the basket bar, the braking effect would be very high.

2. If the biner is allowed to make the half-turn, the two strands slide in the same direction but crossing one another on the underside of the basket bar where the loading would, again, increase the friction but, presumably, not to the same extend as in 1b.

The book mentions the possibility of restoring almost perfect equalization by using a large pear anodized biner combined with manually forcing the crossing to stay above it. Again, more details would have been handy since it seems that you could do the latter either by a) preventing the biner from making the half-turn and making sure that the strands remain side-by-side; or b) letting it make the half-turn but adding some sort of divider to move the crossing from under the basket bar to above it and keep it there during the test. It seems more likely that the authors were referring to the latter scenario but it would have been nice to know for sure.

The equalette, with its two central biners and no twisting or crossing makes a lot of sense as a solution to the clutch problem but, having long climbed with a very minimalist rack, I remain interested in 2-piece anchors that do not involve two central biners. It also seems that the sliding X is still in use by people who have adopted other aspects of the equalette but prefer to stick to a single central locker. So I was wondering if an extension-limited sliding double-X might be an option (assuming that it’s not some antiquated and long-discredited throw-back).

Of course, with the double X, you have to pay close attention to which way you twist the strands and, although the crossings are garanteed to stay outside of the biner, there are two of them instead of one for the regular sliding X. Without further drop tests, it's probably anyone’s guess how well the double X would equalize two unequal arms during a fall. My gut feeling would be « probably better than 1b or 2, about on par with 1a and definitely less well than a 2-biner equalette ».

Thanks in advance for any thoughts or criticisms.

Stéphane

[... ]I twist both strands before clipping them, making sure that I twist them both with the same clockwise (or counter-clockwise) turn. The latter point is vital since, if they are twisted in opposite directions, a failure of one of the two points could let the whole thing unravel. [... ]

I dozed off for a few minutes after the fifteenth `twist´ but I feel better now.

Something like this?

Congratulations! You actually got all the way through the first post and well into the quotation of the 3rd before falling asleep!


Yeah, exactly like that. Nice drawing. Did you do it yourself or get it somewhere (and if so, where?)

More to the point, and in 25,000 words or less, how is this better?

I believe I covered that in the first 400 words but in fewer still: no clutch effect.

Yeah, exactly like that. Nice drawing. Did you do it yourself or get it somewhere (and if so, where?)

Something like this?
[image]http://www.home.no/sittingduck/double_sliding_x.jpg[/image]

do you guys see any problems if you loose one of the anchor legs ?

I mean how these loops are running over each other especially if you use spectra or similar materiall

Seems like enough of an argument to not do it your way.

Nice if there are no clutch effect, that means dynamic equalization. Do you back that sling up?

Well for most of what you do while climbing, there is a right way and any number of wrong ways to do it and it's usually pretty vital that you do them the right way.

No. most of what you do while climbing, there are a number of right ways and any number of wrong ways to do it and it's usually pretty vital that you do them in one of the right ways.

Apologies. You're entirely correct and your post made me realize that my "statement" could be taken to mean that "my" sliding double X is right and the regular one is wrong, which is not at all what I meant. I was simply pointing out that, just because something requires a bit of knowledge and care to execute properly doesn't mean it's bad. We constantly do things while climbing that require knowledge and care and that if done improperly can put our lives even more in danger than they might otherwise be.

All I have to say is I've taken a ton of whippers on a sliding x, on dyneema, spectra and nylon, and I've never seen any evidence of any excess heat/wear on my runners.

More importantly, it's never failed.

And I can tell if it's set up right with a simple glance.

Not saying the sliding double x doesn't have merit, but I'll never use it.

LIAR its a toprope set up or a anchor for multi-pitch climin. WHIPPERS MY ASS LIAR

... or, when you climb on crappy placements, set up gear for a multi-directional load on a traverse.

And, yes, as you say multi-piych. Or really any route that wanders.

Do you need me to explain these further?

That rig is used for much more than TR anchors.

LIAR its a toprope set up or a anchor for multi-pitch climin. WHIPPERS MY ASS LIAR

Not for u top rope tough guy.
Belay or anchor?
U LIAR