Differences in rope diameter


Original Post
JRZane · · Unknown Hometown · Joined Dec 2015 · Points: 0

im in my second year climbing and my first trad leading. I have a 9.8mm 60m mammut rope that has been chopped down to 56m after some sheath damage. I am in the market for a new 70m trad rope and have been handling as many ropes as possible in person while comparing specs.

I guess my main question is in regard to weight/diameter/strength. On longer routes I have noticed the rope getting heavy towards the end of climbs (separate from rope drag) and am enticed by the prospect of a lighter rope. the 9.5mm Petal Arial is rated at 8.8kn, 32% elongation (both similar to the 9.8mm Contact), but weighs 58g/m. most 9.8mm I've looked at weight 62-64g/m. Why use a thicker, heavier rope that doesn't perform as smoothly? I think the answer is the thicker rope will last longer in theory, but does .3mm make a difference? or as much difference as a 70m rope that weighs an entire pound less?

Bonus question: when climbing with another pair of friends, sometimes we top out at the Trapps and wait for the second party to come up so we can tie ropes together and make it down in a single rap. can we tie a 9.8mm and 9.5mm together we EDKs? fishermans? other knot?

thanks!

Brian · · North Kingstown, RI · Joined Sep 2001 · Points: 465

In my opinion/experience you don't need or want a 70m rope if you climb primarily at the Gunks. Most pitches are short and rope drag is an issue on many of the routes if you do them in one pitch. Yes you can tie a 9.5 and 9.8 together with an EDK.

highaltitudeflatulentexpulsion · · Colorado · Joined Oct 2012 · Points: 0

Try not to think of the diameter in terms of what you could measure with a ruler. That .3mm difference is quite significant. It's usually enough of a difference that you can instantly tell the difference between the two.

You're on the right track when you mention grams per meter. Once ropes get fuzzy and dirty, the actual diameter is pretty much nonsense but the gpm is the same. That's ultimately the difference. And pretty much anyone would agree that more material equals more durable.

You mention a heavy rope independent of rope drag. I'll be the contrary one and say that what you're feeling is still rope drag. Even in a perfectly straight line, there is additive friction on every piece you place. If you want to lead long pitches, your best bet is to place as little gear as possible and extend everything you can. The rope, within diameters of common single ropes, is the fourth thing to modify (1. Straight lines, 2. Sparse gear 3. Long Runners, 4. Skinny rope). Consider that and decide if spending money a less durable rope is warranted.

Finally, you are in your second year climbing and climb mostly as the Gunks. Am I correct to assume that your rope sees a fair amount of top-roping? Am I also correct to assume that you're not packing that rope in for miles and doing huge alpine walls with it?

If you ask me, I'd suggest a 9.8-10.2 with the thickest sheath you can find. Elongation and number of falls etc truly pale in comparison to durability.

Ryan Hamilton · · Orem · Joined Aug 2011 · Points: 0

So many variations on ropes of varying thicknesses. Along with feel you'll also want to look at sheath/rope percentages and number rated falls to determine the right rope for you. I really like Blue Water and Petzl ropes for good "feel". Maxim ropes still have a pretty good feel, but the sheath seems to be a little more durable, which I like for zig zagging granite routes and sandstone.

Nick Drake · · Newcastle, WA · Joined Jan 2015 · Points: 438

This link has been posted in the past and has great information. stephdavis.co/blog/straight...

Definitely focus on the sheath percentage and weight more than the diameter spec (which really seems to vary between manufacturers).

I use a 9.8 edelrid boa, 9mm sterling, or 8mm mammut half rope set up. If it's not slab or blocky alpine I usually find drag is much a result of my choice of placements than the rope diameter. Sometimes you just have to make a placement before a traverse as a directional for your follower though. I've found a DMM revolver biner on a QD cuts down on drag drastically for this. You could apply the same idea at roofs.
Also I climb a lot of granite cracks, other times I've had drag it's the rope getting in a crack at a corner. I sometimes place gear simply to keep the rope running out of the crack.

JRZane · · Unknown Hometown · Joined Dec 2015 · Points: 0
Brian wrote:In my opinion/experience you don't need or want a 70m rope if you climb primarily at the Gunks.
see now in my opinion, in my 20 days in the gunks this year, my alternate partners 70m has been awesome helpful there are a handful of 35m rap stations that allow us to get down on a single, and like i said, tying two 70s can get us down from the GT in most places in one rap. maybe its the easier climbs I'm doing compared to yours? I'm usually west of High E with the other sub-5.10 climbers:)

care to be a little more descriptive in why you like a 60 there?
JRZane · · Unknown Hometown · Joined Dec 2015 · Points: 0
Ryan Hamilton wrote:So many variations on ropes of varying thicknesses. Along with feel you'll also want to look at sheath/rope percentages and number rated falls to determine the right rope for you. I really like Blue Water and Petzl ropes for good "feel". Maxim ropes still have a pretty good feel, but the sheath seems to be a little more durable, which I like for zig zagging granite routes and sandstone.
my alternate partner has a new Blue Water lightning 9.8 and that thing handles smooooth. I was actually trying to decide whether to go with that or the Contact when I stumbled into the 9.5 Arial and got to thinking....
Arthur · · Salt Lake City, UT · Joined Feb 2008 · Points: 103

The g/m is definitely the way to think about it. While ropes may have a different feel in the hand, the actual diameter of the rope is governed by standards that the UIAA subjects the manufacturer (5.3.2. of EN 892:2004 is the relevant diameter standard).

The sample of rope is measured for diameter while hanging a static 10kg load (for single lines) on it. So for instance I climb mostly on Petzl and Beal ropes and the Petzl ropes have a really soft hand and almost feel puffy when not under load (so they end up looking fatter than they are advertised at), but under load they get down to their skinny rated diameter.

Also of note is the UIAA standard allows a .2mm deviation from the printed diameter.

http://www.theuiaa.org/upload_area/Safety/Standards/Safety-Standards/UIAA_101_ropes_October_2013.pdf

JRZane · · Unknown Hometown · Joined Dec 2015 · Points: 0
Nick Drake wrote: Definitely focus on the sheath percentage and weight more than the diameter spec (which really seems to vary between manufacturers). .
can you help me interpret sheath percentage specs? not sure what to look for on the spec sheet or what a good/better range would be.
20 kN · · Hawaii · Joined Feb 2009 · Points: 1,128

The sehath percentage spec is going to tell you more about the rope's durability than the diameter will. Of course a 9.1 with a high sheath spec is not going to last longer than a 11mm with a lower sheath spec, but if the diameters are close the sheath spec will tell you a lot.

20 kN · · Hawaii · Joined Feb 2009 · Points: 1,128
JRZane wrote: can you help me interpret sheath percentage specs? not sure what to look for on the spec sheet or what a good/better range would be.
45% - 29%. I've never seen a rope fall outside that range, so that's roughly the min and max. If you get something close to 40%, it should be durable.
Nick Drake · · Newcastle, WA · Joined Jan 2015 · Points: 438
20 kN wrote: If you get something close to 40%, it should be durable.
That's my thought also, but the steeper you are climbing (where the rope is just running over biners and not dragging on the rock) the thinner sheath you can go with. That's assuming you're leading and not setting a TR where the rope drags over rock.
eli poss · · Durango, Co · Joined May 2014 · Points: 136

How much sheath percentage really depends on the roughness of the rock and the style of climbing. I probably do about equal amounts of TRing and leading and I just retired my main lead line to TR duty because it was getting to be too stiff. She was kinda frayed and fuzzy in some spots but it was the core that got worn out faster than the sheath. If you're TRing on some really abrasive rock, on the other hand, you'll want a higher sheath percentage than if you're taking repeated whips on an overhanging sport route on limestone.

Charlie S · · Ogden, UT · Joined Aug 2007 · Points: 1,308

The 9.7mm-10mm range are good all-around, durable ropes. Some wear better than others. I have a 9.7mm and it's my "work horse." 10mm is REALLY tough to feed through belay devices once they get fuzzy or stiff.

I have a 9.2mm for alpine. It's about 1 pound lighter than my 9.7mm. It's for long hauls in the backcountry, not rubbing over edges, top roping, or numerous falls.

For where you're at, I'd aim for the 9.7/9.8. I'll also be a second voice for the 70m. You can cut many of those 3 raps down to 2 at the Trapps. Not to mention longer excursions if you end up in the Adirondacks, Whites, or out west. A 70m has made the difference between comfort and an epic on a few occasions.

Jay Morse · · Hooksett, New Hampshire · Joined Jul 2013 · Points: 30

One advantage of thinner ropes that is often overlooked is that they feed through some belay devices easier and allow a smoother belay. I prefer giving and receiving belays with my 9.5 compared to the 9.8s that most of my partners use. I very much dislike 10.1 and higher, as it seems like it ups your chances of getting short-roped quite a bit.

But honestly, you can't go wrong with a 9.5 or 9.8 and it wont make a huge difference. Think hard about the length you want (70's are heavier, more rope to pull up and manage after each pitch, more rope to stack etc.) and I would go with a bipattern.

JRZane · · Unknown Hometown · Joined Dec 2015 · Points: 0

appreciate the input. The Petzl Arial 9.5 is 40% sheath (more than most), 8.8kn (more than most) 32% elongation (same as most), 58g/m (way lighter than most), and seems to be soft and handle well. it is NOT bi-pattern but is bright ass orange with a black mark. MSRP $260 with their sale, a coupon I have plus rewards points, its $175.

I know many have mentioned the wear and tear issue with a thinner rope, but this one will be used exclusively for multi pitch trad lines. Ive got an older rope that'll be my TR'er.

Ryan Hamilton · · Orem · Joined Aug 2011 · Points: 0
JRZane wrote:appreciate the input. The Petzl Arial 9.5 is 40% sheath (more than most), 8.8kn (more than most) 32% elongation (same as most), 58g/m (way lighter than most), and seems to be soft and handle well. it is NOT bi-pattern but is bright ass orange with a black mark. MSRP $260 with their sale, a coupon I have plus rewards points, its $175. I know many have mentioned the wear and tear issue with a thinner rope, but this one will be used exclusively for multi pitch trad lines. Ive got an older rope that'll be my TR'er.
It sounds like a good rope for what you need. I'd say go for it.
Guideline #1: Don't be a jerk.

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