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sliding X

Original Post
eli poss · · Durango, CO · Joined May 2014 · Points: 525

i've only ever seen a sliding X/magic X done with a skinny dyneema sling. is it effective at equalization with a sling made of 1" tubular webbing with a water knot? does the carabiner slide fast enough to equalize the anchor? what about a 1"x240cm sewn runner or some 7mm cord tied together with two double fisherman's knots? would 6mm cord work better?

FrankPS · · Atascadero, CA · Joined Nov 2009 · Points: 276

I know this doesn't address your question, but the sliding x is rarely needed or optimal. Stick with a pre-equalized anchor.

eli poss · · Durango, CO · Joined May 2014 · Points: 525

i would but i don't feel confident in my ability to tie a master point in a situation where i may take an off axis fall whereas sliding X is pretty simple to set up and takes care of the problem

Paul H · · Pennsylvania · Joined Feb 2013 · Points: 5

Any type of material/sling/webbing should work just fine

eli poss · · Durango, CO · Joined May 2014 · Points: 525
Mike Grobicki wrote: This. Just make sure the bolts you're using are in good shape and you'll be fine.
not using bolts. i have to sling 2 trees and equalize it. does that change your answer?
Ryan Nevius · · Perchtoldsdorf, AT · Joined Dec 2010 · Points: 1,837
eli poss wrote:i don't feel confident in my ability to tie a master point
...what
Ryan Nevius · · Perchtoldsdorf, AT · Joined Dec 2010 · Points: 1,837

If you're climbing, I sure hope you can do this:

youtube.com/watch?v=hpyRlcF…

Brian E · · Western North Carolina · Joined Mar 2005 · Points: 348

Two trees will function the same as bolts. I've found that webbing and spectra cord tends to run smoother through biners and in turn equalizes quicker, but I think that using 7mm cord is fine too. I have found that 6mm cord is much more prone to serious abrasions from the rock.

Tying an overhand or figure 8 on a bight is often preferable to use as a master point. It's not hard, and you probably already "know" how to do it. It might be a skill to become comfortable with when setting up top ropes

ChefMattThaner · · Lakewood, co · Joined May 2013 · Points: 246

If you can not tie a master point please, please do not set up any more anchors. The only benefit of the sliding x is noobs can remember how to do it. Any number of other methods is far superior.

Robbie Mackley · · Tucson, AZ · Joined May 2010 · Points: 85

By eli poss
55 mins ago
From Chattanooga
i would but i don't feel confident in my ability to tie a master point whereas sliding X is pretty simple to set up

Probably best to find someone to teach you in this case.
A magic X used off trees set back from the cliff, could very easily turn your nice self equalizing anchor into a nightmare, when the rope and/or anchor material begins sawing across the edge.
Good luck, and climb safe.
-Mackley

David Gibbs · · Ottawa, ON · Joined Aug 2010 · Points: 2

not using bolts. i have to sling 2 trees and equalize it. does that change your answer?

i would but i don't feel confident in my ability to tie a master point whereas sliding X is pretty simple to set up

Tying a masterpoint is easier than setting up a sliding-X properly. In fact, tying a masterpoint is pretty easy. If you don't feel confident tying a masterpoint, you probably should not be setting up top-rope anchors, or any other anchors.

On the point of two trees -- how big are the trees?

K R · · CA · Joined Jan 2014 · Points: 50

Contrary to what some people are saying, the sliding x is great. HOWEVER, not great for your specific scenario. You would want redundant webbing if using the sliding x in your situation because the sliding x serves as your master point. Instead you should tie an overhand on a bight like others have said. I just want to defend both methods because both are great at times. Sliding x is a good way to equalize and extend two pieces of a 3 piece anchor where there is other redundancy in the system and the master point is something else.

Guy Keesee · · Moorpark, CA · Joined Mar 2008 · Points: 349

Why do you need to equalize Bolts or Trees?

Maybe the worst TCU, anchor, with a high pucker factor... but really.

Jason Todd · · Cody, WY · Joined Apr 2012 · Points: 1,114
Guy Keesee wrote:Why do you need to equalize Bolts or Trees?
This is a great question. In the SERENE equation, equalization is usually the least important component. It is virtually impossible to achieve true equalization in practice.
eli poss · · Durango, CO · Joined May 2014 · Points: 525

i would use and overhand or fig 8 in a bight but I'm worried about taking a fall in which the direction of force may be coming from one side or another rather than straight down below the anchor and the sliding X adjusts to this whereas a pre-equalized knot would not adjust. i am fairly experienced in setting up anchors but never where i had to worry about loading from an abnormal direction. the reason i need to equalize the trees is because one is directly above the end of the climb a few feet back but the other is about a yard to the right and a little bit back from the other. my plan was girth the two trees and extend them just over the edge and then set up a sliding x to create a multi-direction anchor.

FrankPS · · Atascadero, CA · Joined Nov 2009 · Points: 276
eli poss wrote:i would use and overhand in a bight but I'm worried about taking a fall in which the direction of force may be coming from one side or another rather than straight down below the anchor and the sliding X adjusts to this whereas a pre-equalized knot would not adjust. i am fairly experienced in setting up anchors but never where i had to worry about loading from an abnormal direction. the reason i need to equalize the trees is because one is directly above the end of the climb a few feet back but the other is about a yard to the right and a little bit back from the other. my plan was girth the two trees and extend them just over the edge and then set up a sliding x to create a multi-direction anchor.
As Guy suggested above, if the trees are big enough, you don't need to worry about equalizing them. You don't even need two trees - one is enough, if it's well-rooted and adequate diameter. Bingo - one tree, no equalization necessary. But you have to make that call and may feel safer with two trees.
eli poss · · Durango, CO · Joined May 2014 · Points: 525

the trees are well rooted and live but only about 4" in diameter which is why i want to use two. for some people that may be too thin but i put my full weight on them to test them and didn't budge, but as they are not even a thigh-width in diameter i decided it would be better to use two

K R · · CA · Joined Jan 2014 · Points: 50

I've done the same situation you're in. I used two pieces of webbing and two shoulder length slings. The two shoulder length slings made a redundant sliding x which allowed me to TR two routes on one setup with good equalization. Be careful to extend the sliding x to a point where it won't rub on the rock... You don't wanna wreck your slings (mine are expensive... Plus averaging your life line is dangerous).

K R · · CA · Joined Jan 2014 · Points: 50

Another option is to tie a quad and use the webbing from the two trees as if they were bolts.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

The sliding X has been tested over and over again with the same result: it equalizes poorly and unpredictably. This is why Long invented the equalette. The equalization effect gets worse as more friction is involved, so using one-inch webbing is bound to make things worse, and so all told it is not a good solution.

If you are convinced that you need something that will respond to loads from significantly different directions and are using 1" webbing, then an equalette is a better bet.

If the load direction really is going to change significantly, i.e. if the person being belayed may be taking a substantial pendulum, then you have other worries. One would be about what the falling climber might hit. Another is what the effects of the motion will have on the anchor, and whether abrasion might damage it as the anchor rigging is dragged along the lip by a pendulum fall. Remember that if any part of the sliding X gets cut, the whole thing is gone and your climber is dead. The equalette is only marginally better in this regard in that some but not all sections can be severed without a catastrophe. Unfortunately, the most likely parts to abrade would be catastrophic. Something like this is very unlikely to happen in a single fall, the problem would be if the anchors is used over and over for many participants.

If there is a real chance of the anchor rigging being dragged across the lip, then the best solution is to place some gear over the lip, on the face, connect that gear to your trees so that it is fully backed-up, but run the follower's belay rope through the gear. This eliminates dragging the rigging and creates a single master point that, presumably, will withstand loading from various directions and is in any case backed up by the trees.

K R · · CA · Joined Jan 2014 · Points: 50

rgold I didn't read everything but in the first paragraph you say some incorrect stuff. In the same book where long and Gaines present the equallette they show test results for the equallette with equal length arms as perfect and the unequal length arms being 1kn different on a factor 1 fall--the latter being on par with a cordellete of equal length arms (and of course better than a cordellete of unequal length arms by quite a bit). The sliding x equal length was actually the most consistent of all methods across multiple tests.

Edit: third edition. Read it. Also I agree that certain biners and cord can help reduce this variance in force. I use thin spectra slings. Also I would advocate for a quad over an equallette for a 2 tree setup.

Guideline #1: Don't be a jerk.

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