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4mm cordelette?

Original Post
Mike Marmar · · Salt Lake City, UT · Joined Aug 2013 · Points: 67

4mm tech cord: teufelberger.com/en/product…

Has a single strand min breaking strength of 12kN. Sounds plenty strong to me for use as a cordelette.

Other than reduced abrasion resistance, can anyone think of a reason not to use this stuff?

Greg D · · Here · Joined Apr 2006 · Points: 883

So,I used a cell phone the size of a thimble the other day. It was 3 ounces lighter than my other phone, but it sucked to push the buttons on it.

Even if the smaller cord is "strong enough", it will be harder to use, tie, untie, etc. Only to save a few ounces. 6mm is ok, but 7mm is best, IMO.

patto · · Unknown Hometown · Joined Jul 2012 · Points: 25

I used 5.5mm tech cord for a cordalette for a while. I found it far easier to use than 7mm cord.

But now I don't use cordalettes at all. I just use my climbing rope.

Seth Pettit · · Joshua Tree, CA · Joined Jan 2014 · Points: 140

A 6 or 8 foot dyneema sling would probably be just as light/small and was designed specifically for climbing. I like Mammut's because it's tubular.

Max Forbes · · Colorado · Joined Jan 2014 · Points: 108

I'd be concerned about abrasion on something so small. Handling as well.. I'll stick to my quad length dyneema runner for lightweight anchors for now...

Daryl Allan · · Sierra Vista, AZ · Joined Sep 2006 · Points: 1,040

Knots could potentially be a pain to get undone.

Ryan Watts · · Bishop, CA · Joined Apr 2013 · Points: 25
Daryl Allan wrote:Knots could potentially be a pain to get undone.
This.

7mm is where it's at.
NickMartel · · Tucson, Arizona · Joined Aug 2011 · Points: 1,332

One of my 3 cordelettes is 5.5mm titan cord. I really like it, it is light, strong, and not as bulky as a standard cordelette. However, you need to keep in mind that it is static.

M L · · Sonora, CA · Joined Apr 2007 · Points: 165

and also does not respond well to repeated bend/flex cycles or sharp bends.

David Coley · · UK · Joined Oct 2013 · Points: 70

Leaving aside the issue of strength after may cycles etc. one nice thing about thin cord is that it stops most of the cord being in the knot, rather than running to the anchors. Therefore much more flexibility.

The first two photos show how much of a 7mm cordelette can be in the knot and therefore not useful.





The next two compare a 7mm and a 5.5mm cordelette (with the latter not tied in a loop)





(All photos from multipitchclimbing.com)
Kurt Johnson · · Estes Park, CO · Joined Dec 2001 · Points: 2,660

6mm works just fine and I've used it since John Long first recommended and wrote about it way back when. Plus, it's a lot cheaper than 5.5mm Titan cord.

Mike Marmar · · Salt Lake City, UT · Joined Aug 2013 · Points: 67

The cell phone analogy is irrelevant, and in general I find larger bulkier cord to be more cumbersome than the 5.5mm tech cord I use now.

A quad length dyneema sling works fine, but doesn't provide quite the same flexibility as a cordelette. It's not as long, and can't be untied/retied if needed.

Welded knots could be an issue in such a skinny cord, but with 5.5mm tech cord it is actually very easy to untie a loaded knot. I think the stiffness of the cord helps a lot. Not sure how well this would translate to 4mm cord.

I think notmyname nailed it though. From these tests caves.org/section/vertical/… it looks like technora will lose approximately half (!) of it's strength in the first few flex cycles. With the huge margin of 5.5mm cord that's not a problem. However, I would not be psyched if my 4mm cordelette dropped from 12kN to 6kN after the first few uses. 6kN single strand is probably sufficiently strong, but that's cutting it pretty close.

Craig Childre · · Lubbock, TX · Joined Aug 2006 · Points: 4,860

Coley... your just showing off your totem's!! ;)

Sean Burke · · Concord, CA · Joined Jul 2014 · Points: 75

I use a 6mm cordelette for rapping when skiing and doing free solo ridge traverses. For anchor systems I have found it much easier and faster to use Dynex runners from my rack. They are lighter, more versatile, less bulky, and quicker to install than unwrapping a knotted cordellete at the anchor.

Greg D · · Here · Joined Apr 2006 · Points: 883
David Coley wrote:Leaving aside the issue of strength after may cycles etc. one nice thing about thin cord is that it stops most of the cord being in the knot, rather than running to the anchors. Therefore much more flexibility. The first two photos show how much of a 7mm cordelette can be in the knot and therefore not useful. The next two compare a 7mm and a 5.5mm cordelette (with the latter not tied in a loop) (All photos from multipitchclimbing.com)
None of that matters if you do an equalette instead. And even though the rated strength of nylon is lower than most tech cords test show noticeably higher breaking loads in practice because of its dynamic qualities. Plus the addition of limiter knots and cloves provide additional energy absorption points making it even more robust. Better load distribution too. And it's inexpensive to boot.
7mm nylon equalette

Edit to add with an equalettet you need a lot less cord to accomplish the task since each arm is single whereas a cordelette each arm is doubled.
highaltitudeflatulentexpulsion · · Colorado · Joined Oct 2012 · Points: 35

People still use cordalettes?

Why?

My calendar says 2014. Am I mistaken?

Mike Marmar · · Salt Lake City, UT · Joined Aug 2013 · Points: 67
nicelegs wrote:People still use cordalettes? Why? My calendar says 2014. Am I mistaken?
Of course, and I'm sure you know the reasons. Leading in blocks, rope stretching pitches, quicker easier rescue, bail/rap cord, etc.
bmdhacks · · Bellingham, WA · Joined Jan 2012 · Points: 1,633
Greg D wrote:even though the rated strength of nylon is lower than most tech cords test show noticeably higher breaking loads in practice because of its dynamic qualities.
Wouldn't this only apply if you're falling directly on the cord? If you've got a rope in the system then doesn't the dynamism of the rope flatten the force spikes before it gets to your anchor? I just can't see how a nylon cord stretching a few inches is going to add much cushion to my 30 foot f2 fall on a rope that stretches ten feet.
Greg D · · Here · Joined Apr 2006 · Points: 883
bmdhacks wrote: Wouldn't this only apply if you're falling directly on the cord? If you've got a rope in the system then doesn't the dynamism of the rope flatten the force spikes before it gets to your anchor? I just can't see how a nylon cord stretching a few inches is going to add much cushion to my 30 foot f2 fall on a rope that stretches ten feet.
A little research and you will see some drop tests nylon vs dyneema with knots and without. The differences are not trivial to me. YMMV.

Hmmm. 30ft of rope and a ff2. That's a 60ft fall. I'd still rather have nylon with some load absorbing capabilities. But you're pretty much fucked anyway.
highaltitudeflatulentexpulsion · · Colorado · Joined Oct 2012 · Points: 35

People who obsess about cordalettes don't take factor two falls. They say take on every third piece on some low angle nature hike and die on the descent because it always gets dark on them.

David Coley · · UK · Joined Oct 2013 · Points: 70
bmdhacks wrote: Wouldn't this only apply if you're falling directly on the cord? If you've got a rope in the system then doesn't the dynamism of the rope flatten the force spikes before it gets to your anchor? I just can't see how a nylon cord stretching a few inches is going to add much cushion to my 30 foot f2 fall on a rope that stretches ten feet.
I don't have any data on this, put I would guess that most ff2 falls occur very near the belay. To be a true ff2 the fall needs to be clean without the climber sliding down the rock. This means the wall is steep above and below the belay. This means it isn't easy climbing and it would be rare to run out a great distance without protection on overhanging rock.

Hence it might well be that the length of rope in the anchor system might be similar to the length of rope to the climber and together with the various knots there might be this would have an impact on the forces.
Guideline #1: Don't be a jerk.

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