ACR Anchor Method?

JPVallone wrote:If you needed this configuration for what ever reason, then wouldn't the locking carabiner in place of the ring accomplish the same thing without the extra piece of gear?

Yes.

Wehling wrote:I haven't had time to read through the whole link posted by rgold, but in regards to the redundancy, what would people think about tying the ACR out of 2 strands of 5mm mammut procord or something similar. Smaller diameter, but together, plenty strong and now redundant. Small enough that they should slide and adjust reasonably well. Would this be an improvement or do you see a fatal flaw??

No.

Wehling wrote: Or even 4mm cord if we are going to go down this road...

Definitely no.

Mike wrote:People probably hate to see posts like this in threads like these, but... Why not just anchor with the rope instead of bringing all the extra thingamajigs along? You are already tied in to a super-strong, super-dynamic cord. Just use it.

Great option, especially when swapping leads.

Rick Blair wrote:I use a pre-tied equalette. The advantage of this over the equalette is true equalization of up to 3 pieces while the equalette can truly equalize only 2 points. The disadvantage is the better extension limitation of the equalette especially in vertical orientation. I would give the edge to the equalette but I will have to play with this.

Now I'm getting turned on!

Mark Nelson wrote:I say forget those unwarranted fears of shockloading and redundancy, make your anchors distribute loads with solid pro, good angles, and move fast.

Yes! Yes! Oooo. Mark. Talk to me baby.

JPVallone wrote:If you needed this configuration for what ever reason, then wouldn't the locking carabiner in place of the ring accomplish the same thing without the extra piece of gear?

Yes, like stated above, but you would have to incorporate the third loop into the biner, and that would increase rope to rope friction by adding that loop to the mix. At that point, you might as well have a peak at the Sliding X configuration, that would be what it would essentially be.

Joe Lee wrote:There is no redundancy in the cord. If it frays over a sharp edge, the entire system fails.

That problem seems to be addressed by the backup clip-in to the strongest piece.

Looks like I'm a little late here, but I've been using ACR for trad anchors for the last two years. Love it. Very quick setup. I learned it from some crusty Yosemite climbers who made the switch recently. I use 4 or 5mm spectra cord tied together(14-15KN)with a forged aluminum Omega Pacific rap ring (20 KN). Together, the set up is ridiculously lightweight and compact. Less than 3.0 oz.

It's true that there can be extension with the ACR if you're not careful. However, if you have one questionable placement, you can tie ONE leg of the ACR off to minimize extension without compromising dynamic equalization. IMO, ACR does such a good job at distributing load, that there is less of a chance of blowing a marginal piece by unconsciously load-favoring it. But if you really think that two or more legs in your system may blow, then maybe choose a different anchor method. Or find another place to build a belay. But I also tie into the anchor with the rope (not daisy) so there is some sort of stretch in the system if one or more pieces were to blow causing me to fall a couple feet onto the anchor.

The whole thing is perfectly equalized...

Who knows what effects friction will have, but the setup as pictured, in the absence of friction, distributes half the load to the leftmost piece and one-quarter of the load to each of the other two pieces.

What happened to the other 1/4 of the load?

I left an "each" out. Reread my comment, I edited it.

Perhaps I should have said it's as equalized as you are going to get it in a real world situation and left the physics to the math geeks.

Leaving physics to the math geeks is almost, but not quite, as dangerous as leaving mathematics to the physics geeks.

And the ACR, for example, does a better job of equalization.

aaron hope wrote:Looks like I'm a little late here, but I've been using ACR for trad anchors for the last two years. Love it. Very quick setup. I learned it from some crusty Yosemite climbers who made the switch recently. I use 4 or 5mm spectra cord tied together(14-15KN)with a forged aluminum Omega Pacific rap ring (20 KN). Together, the set up is ridiculously lightweight and compact. Less than 3.0 oz. It's true that there can be extension with the ACR if you're not careful. However, if you have one questionable placement, you can tie ONE leg of the ACR off to minimize extension without compromising dynamic equalization. IMO, ACR does such a good job at distributing load, that there is less of a chance of blowing a marginal piece by unconsciously load-favoring it. But if you really think that two or more legs in your system may blow, then maybe choose a different anchor method. Or find another place to build a belay. But I also tie into the anchor with the rope (not daisy) so there is some sort of stretch in the system if one or more pieces were to blow causing me to fall a couple feet onto the anchor.

I've been tying mine out of 7mm perlon, but I really like the look of yours. Does a tremendous job at cutting out the bulk. I think I'm going to head to 5.5mm tech cord. FWIW, I would be very cautious about going down to 4mm spectra cord... that makes your margin of safety VERY thin.

Just another MP douche wrote: Now I'm not a math wizz but I would think that you are actually loosing only 17% of "perfect" equalization? Please correct me if I'm wrong, and please go into great detail. Graphs and perhaps a pie chart or two would be nice.

Sorry, but you are still wrong. And now also imprecise---what exactly does "losing 17% of perfect equalization mean? I gave the theoretical distribution, which, of course, will be modified by the presence of friction (but not necessarily in the direction of better distribution). This particular configuration has been discussed over and over and over, there's nothing new about my comments. Try a search. They've got a whole server's worth of commentary over on rockclimbing.com, for example.

As for the who-needs-perfect-equalization-rant, you're the one who brought up perfect equalization with a set-up that doesn't come close, and you did so in response to a thread about something that does better.

Just another MP douche wrote:Although you've probably got a theory that proves why this is better it seems to be a pretty good instance of where having better equalization would make an overall weaker system.

Now you are arguing with yourself, deciding that the failure of perfect equalization you originally proclaimed is actually a good thing, based on your evaluation of pieces stuck on a woody.

Meanwhile, I haven't commented either way about the need, if there is one, for equalization. I don't use the ACR, I tie in with the rope almost all the time, and my only observation is that of all the so-called equalizing systems, the ACR seems to be about the best.

for those of you who say build the anchor with the rope, what do you do when you don't swap leads? Untie and then tie into the other end of the rope?

Maybe another solution on that kind of switch instead of untie & retie; is 8 bight the rope ends and oppose dual hms lockers making the switch back to lead easier.

Jesse Davidson wrote:fwhat do you do when you don't swap leads?

Re-stack, or flip the stack, or just feed from the bottom.

I don't see that working out when the rope is the anchor.

Justin Baker wrote:What are you thoughts on the ACR Anchor Method: The Alpine Cock Ring Seems kinda cool, but also kidna gimmicky. One concern is clipping a biner to the rap ring. I have always been told biner to biner is bad practice, so is this the same kind of thing?

Have you never clipped a biner to a rap ring (or a chain link for that matter) at a belay station before? There is absolutely no problem clipping a biner to a rap ring, especially if it is a locking biner like you would use at a belay.

Mark Nelson wrote:I don't see that working out when the rope is the anchor.

Oh yeah right.

Either clove the second into a second biner on each piece, or slide the leader's clove out of the way, then clove the second in. Maybe use fig. 8 for the second instead of clove. Fewer strands per biner that way.

rgold wrote:The whole thing is perfectly equalized... Who knows what effects friction will have, but the setup as pictured, in the absence of friction, distributes half the load to the leftmost piece and one-quarter of the load to each of the other two pieces.

Not trying to start anything here but I am not sure how you get this. Can you explain a bit more or point somewhere that does? Here is what I get:

If we neglect friction, we can assume that the tension in the cord is constant. We'll call that T. Each arm has two cords so isn't the force on each piece simply 2T? It seems (in a frictionless world) to be perfect balanced, regardless of the geometry.

Again, not trying to be a smart-ass, just a geek.