How to Choose a Rope
It doesn't matter if you're a 5.2 beginning climber or a 5.14 rock slayer, whether you wear Carhartts or neon lycra at the crag, every climber out there shares one thing in common; at some point our lives depend on our rope. As of late, rope manufactures have done an incredible job at making ropes lighter, stronger and most importantly, safer. However, along with all the improvements the consumer now has a lot more choices. This will be an attempt at clarifying some of these choices and offer some advice when choosing a rope for your next adventure.
Understanding the LabelsWhen shopping for ropes you will notice a variety of "technical specs" included by the manufacturer. By understanding what these numbers mean, you can better understand how a rope will perform and if it is going to be a good choice for you and your climbing. First, every dynamic climbing rope commercially sold should be marked with CE and or UIAA. This indicates that your rope has passed a set of controlled safety tests. Along with these markings, most companies will include an impact force rating along with dynamic and static elongation numbers. It is well known that the stretch in our rope plays a major role in our safety system by absorbing energy in a fall, thus reducing forces on our gear and our bodies. A lower impact force number means less energy will be transferred to your protection. This can be important if you are climbing in areas where gear is less reliable such as ice, soft rock or thin gear. However, while a low impact force will increase the chances of your gear holding, it normally translates into higher elongation numbers meaning more rope stretch and a longer fall. So, for higher-end climbing or ice climbing, choosing a rope with a low Impact force rating may be a good idea, but for general sport climbing and top roping it may be unnecessary or even inappropriate.
Manufactures also often include a "UIAA falls held" number which may seem astonishingly low at first glance. However, this test essentially creates a "factor 2" fall scenario (the worst case scenario where you fall twice the distance of the amount of rope out) and is repeated until the rope breaks. Since "normal" climbing falls typically register below a fall factor 1, this number is not necessarily representative of how many falls your rope can handle. Nonetheless, this number will give you insight into the durability of your cord. For example, take an 11mm rope that is rated to 16 falls or a 9.2mm rated to 6 falls and guess which one will last longer.
The Single Rope This is the most common type of climbing rope used and there are seemingly endless choices out there, so let's take a closer look at some of the options. Probably the most obvious difference between ropes is the diameter. Don't quote me on this but as of now, I believe the smallest diameter single rated rope is a slim 8.9mm. For all the light and fast junkies this sounds like a dream come true, but keep in mind light doesn't always mean right. A skinny rope will not be as durable, will have more stretch and won't work with every belay device. If you are looking for a rope to use after you do that three hour approach or want the lightest rope out there for your hard red-point and durability is a secondary concern, then go with a skinny cord. However, if you want a rope to work projects, use on big walls, top rope on or last a full season, you may consider something a little beefier. Half Ropes and
Twin Ropes While very popular in the UK and Europe, the double rope system hasn't quite taken off in North America. However, once understood and practiced, a double rope system can be very advantageous in certain situations. First off, the difference between the half rope (marked ?) and twin rope (marked ?) is while both ropes are intended be used in pairs, the half ropes will be clipped independent of one another while the twin rope will be clipped together through protection. Because of this, half ropes will be better suited to wandering pitches and can virtually eliminate rope drag if used correctly. Also, because you are only clipping one rope, the half ropes have very low impact force ratings which will be nice on less than ideal gear placements. Furthermore, one half rope is considered acceptable for glacier travel. Twin ropes, while similar to half ropes, tend to be lighter and more user friendly for first time users. Since you are treating the two ropes as one, it is easier to belay with twin ropes and twists in the system rarely become an issue. These ropes also have quite low impact force ratings making them a popular choice for ice climbing and alpine climbing.
The Tag Line While North American climbers may be less familiar with double rope systems, especially on rock routes, everyone seems to be familiar with a tag line. Here, I mean leading a pitch on a single rope and trailing a skinnier rope, which can then be used to haul gear or rappel. I think this is a great system if you are climbing a route at your limit. It allows you to climb on a single rope (often easier to clip and easier to work a route with) and then haul up any extra gear, shoes or water in a small pack. Therefore, you don't carry any extra weight on your lead. While this can be a great system it is important to keep some things in mind. A skinny trail line is compact and light, but I find they blow around in the wind more and get caught more readily on flakes, branches etc. Also, most (if not all) trail lines are not intended for lead climbing, so if your lead line gets stuck on a rappel you could find yourself in a very tricky situation without a suitable rope to climb back up and get it. Finally, an ultra thin tag line will require a different system to rappel on than normal ropes. Because of the large diameter difference, you will need to set up your tag line as a retrieval cord rather than simply tying the two rope ends together as you would on a normal rappel. Due to these reasons, I personally like to trail a twin or half rope instead of an ultra thin cord. While this does weigh more, it gives me some security if my lead line gets stuck or damaged - you can always tie into the middle of a twin rope and lead on it safely.
IMO We've come to the point now that where I get to share my personal preferences. For rock, I like a rope in the 9.4 neighborhood for higher end routes (the Blue Water Dominator being my favorite lately) and something like 9.7 or 9.9 for everyday cragging. For routes requiring multiple rappels to descend, I prefer to take a set of half ropes opposed to a tag line. However, if I'm trying a route at my limit, I'll go with a tag line and typically bring a twin rope for that. For ice climbs I like half ropes and in the mountains for alpine climbing I've been leaning towards twin ropes because of the weight savings and how compact they are. If you are using your rope in winter, pay the extra money for the dry treatment. Also, think about where you will use your rope most and choose a length accordingly; a 70m is great in Indian Creek, but too much rope to carry if your Alpine climbing in the Alps.
Of course not everyone wants to buy multiple sets of ropes and not everyone has the need for them either. If your climbing interests are diverse and take you through the four seasons I would suggest going with a mid-diameter single rope (9.9ish) and a set of half ropes all 60m long. This will give you a lot of options and allow you to pursue any type of climbing safely and in style.