Ideal size for double ropes

After recently being introduced to the double (half) rope system, I'm looking to pick up a set for use in trad, ice, mixed, and alpine climbing (in priority order, trad being the highest). I'm in Boulder, so the front range locations are my primary focus. I will travel outside the area, though, in case that matters.

Anyway, given that, what's the ideal size for doubles?

In terms of diameter, 8mm seems like a good starting point. I don't see much of a reason to go above that due to the extra weight. Is it worth considering ropes 50m. Thus I'm leaning towards 50m (vs 60m). Thoughts?

Thanks all!

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That last paragraph should read:

In terms of diameter, 8mm seems like a good starting point. I don't see much of a reason to go above that due to the extra weight (yeah, it could cut easier, but that's one of the reasons why you have doubles). Is it worth considering ropes less than 8mm? I think you start to run into problems with belay devices below 8mm. As for length, I can't imagine there are many (any?) pitches longer than 50m and 50m should certainly be sufficient for any normal descent rappel. Thus I'm leaning towards 50m (vs 60m). Thoughts?

Thanks again!

go the 7.7

I'm a big fan of twin/half rope systems for alpine and ice, and some "regular" trad (like long multipitch climbs with rap descents). My favorites are the PMI Verglass, which are 8.1mm. Bluewater makes something called Ice Floss, which are 7.7mm, but they are only rated as twin ropes, and I like the flexibility of ropes that are rated for either twin or half use-- you can tailor your technique to the demands of the pitch.

I own an older set of PMI twin/halfs that I believe are 7.8 or 7.9. I would not want to go quite that thin next time. I would not go lower than 8, personally. I have found the 7.8s slip a bit too fast on rappel using some older belay devices (old-style ATC, or an HB Sheriff). If you extend the device away from your harness for the rappel, then most will hold well enough. But with a heavy pack on, I have found even on rappel devices that are rated to as low as 7.7 (such as the Trango B-52, which I use often), it still feels like I could get going pretty fast if I don't keep a hard breaking angle on the ropes.

The weight difference between an 8.1 and a 7.7 doesn't justify it, in my mind. Edelrid now makes a crazy-thin rope (Flycatcher -- 6.9mm!) that has specs comparable to the rest of the twin/half ropes out there (9.8Kn impact force -- a bit high for twins, but still within the acceptable range). But they're quite expensive right now, and you can only use them with one dedicated belay device made specially to handle them, so BOTH climbers in the party have to invest in the belay device, or you have to buy a second device to lend to your partner each time.

I think 60m is the right length. Sure, 50m would be lighter, and two ropes- no matter how thin- are a bit heavier and bulkier than a single 70m rope, say, of less than 10mm width. However, there are other places in your kit to focus on weight reduction (basically all your non-climbing stuff like jackets and packs first, then maybe your draws). I think a 50m set of doubles would negate some of the advantages of doubles in alpine terrain, which include looong pitches and hasty retreats (no need to bring a tagline for full length rappels). As 60m and even 70m ropes continue to infiltrate each category of climbing, and as sport climbing and trad continue to interbreed, I think the placement of fixed rappel anchors and such even in alpine settings is likely to trend toward longer pitches. The day could come when 50m ropes just won't get you to the next established rap station. But even if that day never comes, 60m just gives you more flexibility for not a lot more weight and bulk, and while the extra $$$ it would take to jump on the 6.9mm bandwagon in their very first year of production may not be worth it yet (I am open to being convinced), the extra $$$ to go from 50s to 60s is, in my opinion.

Have fun out (up) there!

If your primary focus is Trad climbing I think 8.5mm x 60m is your best best for a good all round setup. The skinny half ropes are really meant for alpine use where you're really not using them for wandering pro and falls on a single strand as much.

60 M, no thinner than 8.4. For me, the thinner ropes are just plain scary. Here is my reasoning: Rap on a set of 7.9s and think about how much less friction you get from your belay device than when you use thicker ropes. Then, think about catching a big whipper with the same 7.9s. I have no concerns about the skinny ropes breaking or being more prone to being cut. It is the loss of stopping power when catching a fall that worries me. YMMV, and I am sure that there are a lot of folks out there that have a very different opinion.

Been using double ropes for 5 years. My advice is don't go below 8mm and do get 60m. There are plenty of rappels that are the full 60m. I love my Eidelweiss Oxygen 8.2 doubles and they are still in great shape after 5 years, a trip to patagonia, and lots of alpine climbing.

For ice/alpine, I have and like the Metolius Monster 7.7 doubles/twins. They offer the distinct advantage over the Ice Floss 7.7 which are rated for twin use only.

For trad, I have and like the Mammut Genesis 8.5mm. Burlier and more abrasion resistant than the Monsters.

I wouldn't get 50M ropes for any reason at all. There are too many modern climbs being put in with 60M length pitches/rappels.

I've been happy with my PMI verglas 8.1 60m half/twin ropes. I've used and liked a friend's 8.5 mammut genesis. Have used some 7.7 sterling twins solely on ice and have definitely noticed the lack of friction on rappel.

I would definitely say 60m over 50 and would recommend 8mm or more.

EDIT - I would also recommend a dually certified half/twin rope as someone already mentioned to maximize versatility.

I bought some double Mammut 8.4's a couple of years back and they've performed well... But since you listed general 'trad' as your highest priority, I figured I'd throw this out there... I thought I would use my double ropes a lot more than what I do. For me, the disadvantages of a double/twin rope setup usually outweigh the advantages... It's a hassle for me to deal with 2 ropes through gear on lead, and I tend to fumble. I also don't tend to be as comfortable falling or catching falls on the doubles.

So when 2 ropes are necessary for raps, I've found myself preferring a system of 1 standard lead rope (say 9.4-9.8mm) and 1 thin tag line (say 7mm). You can tail the tag line up easily as you're climbing on a standard lead line that you're comfortable falling on, comfortable with gear placements, etc. Those subtle differences in familiarity/comfort make a world of difference for me when I'm pushing the difficulty or in a more serious /alpine setting. Also tag lines are much cheaper and more expendable, so I find myself more willing to cut them up for improv anchors & rescue situations. The overall system is cheaper, comparable in weight, and (for me) more versatile.

...just something to consider

^^^^ ditto

i have a pair of 8mm 70m which i only use for long wanderingmulti which require full length raps

for general cragging or more straightforward multi i use a 9.5-10.3 mm and a half rope as a tag line ... especially if ill be taking multiple whippers, or my partner is gonna hangdog to figure out the moves

for long multi ~8mm ... for trad cragging ~8.5mm

I've been climbing on half ropes (almost exclusively) for maybe thirty years. They get heavy use on a regular basis, 'cause I use 'em for everything. Although a bit on the weighty side, I like 8.5's. They stand up to lots of wear and I, at least, don't have a second thought about falling on a single strand. I've used other half ropes, and I think that the thinner ones may be more prone to tangling.

Ever since they've been available, I've used 60's. If you intend to climb regularly on the small crags of the UK, 50m is standard there. In this country, you'll find 60's more useful.

Thanks all! This is awesome feedback! I'm definitely sold on the 60m length.

I do have one question regarding the dual double/twin certification, though. I can understand why twin-only might be overly restrictive (e.g. having to clip both ropes in every piece of pro on a wandering route). Can someone help me understand why double-only is limiting, though? In other words, are there situations in a double rope system where I would want to clip both ropes vs just one?

I'm probably missing something but intuitively it seems like you'd just be upping the impact force on that single piece of pro which then makes it more likely to fail (assuming you want to clip both because it's an important placement above a ledge or perhaps the belay).

double only isnt really limiting at all.

Most people unless climbing ice wont be using a twin setup.

The ONLY place I've found using a TAG LINE system useful is at the CREEK or other areas where the routes are pretty plumb line and single pitch. Any multi-pitch route that requires many raps to get down ends up being a PITA. The Skinny Tag line tends to tangle (thin static tends to be even more tangle prone than thin dynamic), is more prone to hanging up when you pull it AND will not serve as a backup rope if something goes wrong and the lead line hangs up.

Twin/Half rated ropes are most useful where you'll climb the route in a more single rope style but will/may have the need to rap down the route (Weather, bail due to difficulty etc). Red Rocks (Black Velvet Wall) comes to mind. The lighter weight of the "twins" size but larger "safety factor" of the half rope rating is a nice combo.

Larger Half Ropes, as other have pointed out, are more useful in trad "cragging" setting than the high alpine or long direct routes.

I have a set of 7.9mm Twin/Half ropes for the long and direct route with rap offs.
I have a set of 8.8mm Half ropes for cragging etc (60m halfs in the Gunks are fantastic) I have also used them a fair amount at Squamish where I wasn't 100% confident in the weather and/or my ability to send that day as well as long climbs in a party of 3.

One thing that needs more emphasis is that with the really skinny lines (8.1ish and below) one really needs to be mindful of how LITTLE friction they have. You need a GOOD belay device and GLOVES. One of my scarier moments climbing was rapping down Prince of Darkness with my new 8.1s and a 1stGen Reverso (no V slots) I got more pumped on the rap than I did climbing.

8.5mm x 60m Half ropes will serve you best as a first set. You'll figure out where/when you might want the skinny version as well as when to use a single lead line to save wear and tear on the halves

MattM: "You'll figure out where/when you might want the skinny version as well as when to use a single lead line to save wear and tear on the halves"

That's why I love my Beal Joker 9.1. Yes its thick when running doubles (comforting when extra sharp edges surround you) but the option to switch to a single is money (Joker = rated for double, single and twin)

You won't find your answer listening to us, go out and experiment so you can KNOW what you want/like/prefer.

BTW, thanks all for the great advice! I ended up going with dual 60m Bluewater Excellence 8.4mm ropes and they are perfect. Having climbed and rappelled on them a few times now, I can see how something closer to 8mm would be a little sketch. It's amazing what a difference those fractions of mm's make!

mattm wrote:One thing that needs more emphasis is that with the really skinny lines (8.1ish and below) one really needs to be mindful of how LITTLE friction they have. You need a GOOD belay device and GLOVES. One of my scarier moments climbing was rapping down Prince of Darkness with my new 8.1s and a 1stGen Reverso (no V slots) I got more pumped on the rap than I did climbing.

Peter Franzen wrote: Running the rope through 2 'biners under the rap device instead of one provides considerably more friction, and eliminates the need to bring gloves.

This thread is really old, but for the sake of anyone else that finds it when researching double (half) and twin ropes, there IS INDEED a situation where double only ropes are a hindrance:

If you are counting on belaying two followers on a traverse, and you want to protect them both, you're probably going to want to clip both ropes to all of your pro.  But that will set you up for a potentially very high impact force should you take a whipper.  It's a pretty specific situation, granted, but probably worth noting.