Diameter vs weight/meter

[shaoleung]

In a recent coversation with a friend we were comparing spec sheets on ropes while I try to figure out a good, durable, rope for alpine. We were looking at the grams/meter instead of the mm rating given bythe manufacturer. The grams per meter seem to give a more reliable sense of the rope durability.

 

I am trying to figure out why of all the specs on ropes, the most commonly referenced is the diameter. I usually carry "a 10.2" but I am thinking if I pick one stat from the specs it should be the weight... Thus I will buy a 9.9mm rope next and call it my 65g.

 

Flawed logic, epiphany or genius?

[kevino]

Thats because they are classified by their diameter, not their weight. Its like saying, oh yeah i have my 2 lb sleep bag with me.

Edited April 11, 2010 by kevino

[shaoleung]

Thats because they are classified by their diameter, not their weight. Its like saying, oh yeah i have my 2 lb sleep bag with me.

 

We talked about that, but it really isn't like using weight for comparison. Sleeping bags vary so much in the type of fill, that temperature ratings have more meaning.

 

Rope widths on the other hand seem to be the more subjective number when compared to gms/m. Measuring nylon rope down to the tenth of a millimeter is somewhat futile when the diameter can vary significantly depending on temperature, moisture and weave. While girth is somewhat important, we all know that strength and how long one lasts trumps all else.

[summitchaserCJB]

Sounds like your trying to over-intellectualize this to me. I guess you could compare similar diameters on gms/m. That really is a more realistic comparison, given that people want different diameter ropes for different applications. If you want the lightest rope, google around or ask someone and they'll let you know and you can buy it. For alpine routes I like my 9.1 Joker.

As far as the theoretical conversation goes, I think the current standard is fine.

[summitchaserCJB]

And I'm sure they have a standardized way to determine width (at least you'd think they would). You know, at a given temperature under standard conditions. Ya, it'll change in the field, but they have to tell you something. If there were just 9, 10, 11mm ropes that would significantly limit the number of available ropes. I don't think they should stop manufacturing 9.1 ropes just because it might not always, 100% of the time be 9.1mm exactly. I think asking that might be a little anal retentive.

[Dane]

"while I try to figure out a good, durable, rope for alpine"

 

Helps to first decide what your priority is, weight or durability.

 

The catch is when you want a light and durable rope.

 

No trick to it, ropes are all made of nylon. Fat ones are more durable than skinny ones. Heavy ones more durable than light ones. Diameter is just a starting point, as weight per meter is a better indicator of durability.

 

For a light weight single, I am a Joker fan myself. Some good 1/2 ropes out as well that will work as a single in the right conditions.

[shaoleung]

One of the issues that came up when we looked at rope specs was that the variance in gm/m among 10.2 ropes can be greater than the gm/m variance between 10.2 and 9.9 ropes.

 

At least one manufacturer discontinued a 9.7 and introduced a 9.9 where all the specs (aside the diameter) were exactly the same. No change in weight, strength or stretch.

 

In any case... time to shut up and climb. I've settled on a 10.2/67gm/m Monster.