The Mini-Quad

Stagg54 Taggart wrote:

I don't quite understand the sudden attraction to the "quad"...  Seems like a solution in search of a problem...

I wouldn't call it "sudden"! It took awhile for guides to embrace it and even longer for it to become more common recreational-ly, from my limited perspective at least. While others have already pointed out this wasn't a sell on the Quad more a version of it for those who already use it. I will add that having two independent redundant "power-points" is what really won me over to the original Quad as I spend a lot of my time climbing in a party of three (guiding). So I'll clove into one power point, belay off my anchor carabiner, first client cloves into free power-point, 2nd cloves into the loop I am in (and about to leave), which leaves them more movement/comfort while I lead the next pitch... none of those awkward "carabiner shift" moments... we've all experienced that! All the other bonuses already mentioned are icing on the cake. I'll break out a traditional cordelette at a gear anchor less than 1/10 of the time. Quad is faster, by a noticeable amount.

Some gear company is gonna come out with a sewn version, I’ll bet.

Alex

So are you just clipping into two strands? I always thought that it was supposed to be clipped into three. It's super hard to figure out which pair of strands is actually paired, esp. with the tiny dyneema knot.

jg

Josh Gates wrote:

So are you just clipping into two strands? I always thought that it was supposed to be clipped into three. It's super hard to figure out which pair of strands is actually paired, esp. with the tiny dyneema knot.

jg

I don't get that. The pairs are isolated by the knots. Pick any two. (Not that I use a quad)

 Studies I've seen show a 50 to 60% reduction in strength when knotting dyneema.  Furthermore, these tests are with freshly tied knots.  Dyneema is quite slippery and knot tightening will play a role in energy absorption. But, in you're permanently tied quad those knots are tighter and tighter and have lost their ability to absorb any energy.   I would estimate your rig is only good for 2000-2500 pounds. Some posters above have dismissed this due to the redundancy. But if one loop is only good for 2000 pounds then the entire rig is only good for 2000 pounds. I would avoid high fall factors onto any anchor, but, especially with this rig.

Northeast Alpine Start wrote:

All good points. And while using the rope is a very valid (and lightest) option out there it really only works well if swinging leads, which I never do. Block leading is so much faster than swinging leads on long routes, when a block is ending using the rope is a valid option.

Eeh, what?? Totally disagree. If you're using this new-fangled latest-and-greatest invention of a mini-quad, you have "cooked down" your anchor into two points before attaching your quad. Simply skip the quad and use the rope to attach yourself to those same two points. Follower does the same. Simple, no need for additional "special-use" gear. Just two biners each for leader and follower. No trouble for either block leading or swinging. 

Yes, if you're hauling around a team of three or four climbers, a standard masterpoint is probably beneficial. 

Yes, for a true hanging belay, a standard masterpoint is prefered.

Yes, block leading is a bit of a mess if you tie into three or four (or 27) different trad pieces with your rope. But if you "cook down" your anchor into two tie-in points (which is needed for this quad anyway), there is no mess at all. That's what I do 93.87% of the time and none of my partners have had any complaints once they overcome the "fear"/confusion of not seeing a traditional masterpoint.

Just to add another iteration of the "mini-quad" to the mix. I occasionally use a tripled 240cm dyneema sling as a pre-rigged quad. This gives me a little more length than a doubled 120cm, adds a layer of redundancy (three-strand master points instead of two-strand), and should (at least in theory) help the reduced-strength situation by creating beefier knots (more absorption) and creating the opportunity to spread the load a little more among individual strands.

Of course, for those that care, this has all been covered already in this thread from August.

Also here, in another thread from August.

Greg D wrote:

 Studies I've seen show a 50 to 60% reduction in strength when knotting dyneema.  Furthermore, these tests are with freshly tied knots.  Dyneema is quite slippery and knot tightening will play a role in energy absorption. But, in you're permanently tied quad those knots are tighter and tighter and have lost their ability to absorb any energy.   I would estimate your rig is only good for 2000-2500 pounds. Some posters above have dismissed this due to the redundancy. But if one loop is only good for 2000 pounds then the entire rig is only good for 2000 pounds. I would avoid high fall factors onto any anchor, but, especially with this rig.

Could you share some links Greg? Actually it's still a moot point IMO. And knots weaken Dyneema and nylon. They also help create redundancy and limit extension, which is often more important than the loss of material strength.

You are correct that Dyneema has virtually NO energy absorbtion, whether it is knotted or not, but that is also moot if you are connecting to the anchor with a dynamic attachment (climbing rope or Petzl Connect) and watching your fall factor. I'll point out if you ever end up putting 2000 pounds of force on your anchor you have issues no matter which system (Quad, Cordelette, using the rope) you employ. Those types of worse case falls are career enders.

wivanoff wrote:

I don't get that. The pairs are isolated by the knots. Pick any two. (Not that I use a quad)

I agree - found a couple of references that said three, for more strength, but then it means only one on one side in the event of failure of one leg. Question retracted.

Northeast Alpine Start wrote:

Could you share some links Greg? Actually it's still a moot point IMO. And knots weaken Dyneema and nylon. They also help create redundancy and limit extension, which is often more important than the loss of material strength.

You are correct that Dyneema has virtually NO energy absorbtion, whether it is knotted or not, but that is also moot if you are connecting to the anchor with a dynamic attachment (climbing rope or Petzl Connect) and watching your fall factor. I'll point out if you ever end up putting 2000 pounds of force on your anchor you have issues no matter which system (Quad, Cordelette, using the rope) you employ. Those types of worse case falls are career enders.

Any reason to (or not to) build this out of nylon, then, for the dynamic properties (which usually are provided by rope, etc., but hey, maybe there's some case where it'd make a difference)? I'm not generally a dyneema truster - I even got a PAS made from nylon instead of dyneema. I like stuff that can stretch a bit.

Josh Gates wrote:

Any reason to (or not to) build this out of nylon, then, for the dynamic properties (which usually are provided by rope, etc., but hey, maybe there's some case where it'd make a difference)? I'm not generally a dyneema truster - I even got a PAS made from nylon instead of dyneema. I like stuff that can stretch a bit.

The article talks about nylon's water absorption.

Serge Smirnov wrote:

The article talks about nylon's water absorption.

That's true, though I always discount that, since I don't climb in the rain :)

Maybe I'm missing something but is there any reason I'd not just make a "mini-quad" out of the same cord as my cordelette that I often tie into a "traditional" quad? Just use a shorter piece?

Serge Smirnov wrote:

...  Sliding X with limiter knots offers poor equalization.  If you clip into only one side of the X you get good equalization but no redundancy for that bottom segment of the sling.  Not everybody insists on having both of those features, but for those who do - the quad offers both.

I'm not following you (might just be me).  I see the sliding X being identical to the equalization of the quad - the only difference is that the "masterpoint" is shared by the biners in the X and split on the quad, and still redundant in both cases.  The movement between the limiter knots is identical.  What am I missing?  (Honest question here, I'm just not seeing it)

I *think* what keeps the sliding X from equalizing is the need for 2 sling segments to move in opposite directions - their friction against each other prevents the motion.

Serge Smirnov wrote:

I *think* what keeps the sliding X from equalizing is the need for 2 sling segments to move in opposite directions - their friction against each other prevents the motion.

+1 There's quite a bit of friction there, worse when it's under tension. Pull on the MP biners for both sliding X w limiters and quad and try to slide it side to side: much harder with the X.

Northeast Alpine Start wrote:

 but that is also moot if you are connecting to the anchor with a dynamic attachment (climbing rope or Petzl Connect) and watching your fall factor. I'll point out if you ever end up putting 2000 pounds of force on your anchor you have issues no matter which system (Quad, Cordelette, using the rope) you employ. Those types of worse case falls are career enders.

2000 lbs is not that hard to achieve.  Lead falls (with dynamic rope) can exceed this force on the top piece.  So, what if you have a high fall factor such as a fall before getting your first lead piece in?  Or your first lead piece fails, then you fall onto your anchor.   As I stated above, this should be avoided at all costs.  But, it can happen.  

Personally, I would prefer a quad (mini or maxi) made out of nylon cord and loosening the knots periodically.  YMMV.

I like the mini quad. Especially in the guide/client use case, and double especially when there are bolted belays.

I don't like the idea of leaving the knots always in. It reminds me a bit of the Todd Skinner situation where the knotted sections (or in Todd's situation, his belay loop) gets a bunch of extra wear in it. I untie mine every night.

Also, I don't like to use the ultra skinny dyneema for these. I purposely use one of the fatter ones. The knots are stronger and easier to untie. http://dmmclimbing.com/knowledge/knotting-dyneema-vid/

Northeast Alpine Start wrote:

Could you share some links Greg?

Well, I've seen published data many times over the years. But I don't  have a link.  Feel free to do a search.  But this video shows a reduction in strength of 45% and 51% from an overhand knot in dyneema as one example. 

http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/

One subtlety about knots weakening slings is that those same knots can reduce peak forces.