Rope Question - Mammut 8.5mm Genesis Dry Rope

Hi, I just bought this rope for use as a single rope. Based on the sticker, it appears to be be a twin/ half/double rope.

I plan on using it mainly for 1-2 pitch cragging and the occasional multi-pitch climbing as well as some soloing here and there. My friction devices are the REVO and the MegaJuul (which it it runs really smooth thru on lead and rappel and seems to catch no different than other greater diameter rope.

Reason I bought it for use as a single rope:

1) it is super light (5 lbs or so)

2) Impact force is about the same (unless I am reading it wrong) as other single ropes

I have never owned such a skinny rope and curious to find out what your take is: if you have used a rope as such in a similar manner.

Here is a link: https://www.mammut.com/us/en/p/2010-02801-11146/85-genesis-dry/

Why would you use a rope that's not rated single-rope, as a single-rope?  You might be able to get away with it, but I'd be too skeered of it cutting over an edge.

I'd say you should ask Mammut, but you know what they will probably say. 

On the other hand, if it's not rated as a single, why do they list the number of falls for a single? 

Sorry I'm not any help.

FrankPS wrote:

Why would you use a rope that's not rated single-rope, as a single-rope?  You might be able to get away with it, but I'd be too skeered of it cutting over an edge.

I'd say you should ask Mammut, but you know what they will probably say. 

On the other hand, if it's not rated as a single, why do they list the number of falls for a single? 

Sorry I'm not any help.

The falls Mammut is quoting are for twin rope and half rope tests, not the standard test drop for single-rated cords.

Gunkiemike wrote:

The falls Mammut is quoting are for twin rope and half rope tests, not the standard test drop for single-rated cords.

Thanks, Mike. So when they specify the number of falls for "single rope," they are talking about when a pair is used as twins? Why don't they say "used as twins" or something to that effect? (rhetorical question)

Disclaimer: I don't know the first thing about anything.

I was under the impression that cord diameter does not make an appreciable difference in terms of cutting strength.  I recall seeing some data, but can't come up with it right now...
The main difference in rating has more to do with rope stretch (half and twin need to stretch more so that the impact force is lower, to avoid a tension break (terminology?)).  I wouldn't want to be taking long falls on a half rated cord for fear of falling too far and hitting something.  Though I suppose that depends a lot on the terrain.

I've also seen some thoughts on using a half rope as a single for lightweight climbers, since the single 80kg test is overkill for a 50kg climber, for example.  The half rope test of multiple 55kg falls is more germane to a 50kg climber.  This becomes more reasonable if the cutting strength is not effected, like I mentioned.  See this link

FrankPS wrote:

Thanks, Mike. So when they specify the number of falls for "single rope," they are talking about when a pair is used as twins? Why don't they say "used as twins" or something to that effect? (rhetorical question)

When Mammut say "double rope" read 2 rope as in twin. They test the ropes as a pair. 80kg drop weight.

"Single rope" in this case refers to testing 1 rope of the two. 55kg weight. This is the way we use 1/2 ropes, clipping them one at a time.

rocknice2 wrote:

When Mammut say "double rope" read 2 rope as in twin. They test the ropes as a pair. 80kg drop weight.

"Single rope" in this case refers to testing 1 rope of the two. 55kg weight. This is the way we use 1/2 ropes, clipping them one at a time.

Funny. And confusing, but thanks for clarifying!

Mammut must know the difference between the twin and double rope terms, yet they treat the terms the same?

Their 8.7mm rope is rated as a single, double and twin. Just get that if you’re thinking about using it as a single line.

I use the 8mm mammut phoenix half rope as a single rope in the alpine for simulclimbing and stuff well within my grade.  The UIAA drop test leaves a HUGE margin of error and IMO actually holds back the development of smarter, harder to cut ropes.  Unless you plan on taking huge factor 1+ whippers on the rope repeatedly, you are never going to break a rope.  In fact, I have never seen a published case of anyone breaking an undamaged kernmantle rope ever from a fall.  As for cutting the rope I would argue that good quality half ropes are safer than most skinny sub 9mm ropes because they have more sheath.  The way rope manufacturers meet this uiaa standard in skinny ropes is by dropping the sheath percentage in most cases.  

Put simply:

#1  A 8.5 with 45% sheath proportion is less likely to get core shot than an 8.7 with 32% sheath. 

#2  People die from cut ropes, not from "breaking" ropes in falls.

All of that said, If you are planning to just crag with it all the time, I think that is not the greatest idea if you are going to be taking repeated falls.  For a daily "working" rope I think something a little thicker is in order. For occasional use and for select alpine missions I personally have zero problem with it, but I work that out with partners beforehand.  You obviously have to make that decision for yourself. 

Cool and thanks. Very good in depth article!!

Nick Baker wrote:

I use the 8mm mammut phoenix half rope as a single rope in the alpine for simulclimbing and stuff well within my grade.

When I do this, I have one climber tie into the middle and the other into the two ends. That allows you to utilize the benefits of double/half ropes while also being able to communicate better.

Marc H wrote:

When I do this, I have one climber tie into the middle and the other into the two ends. That allows you to utilize the benefits of double/half ropes while also being able to communicate better.