登山绳主要有两种类型：动力绳和静力绳。动力绳的设计目的是为了延伸以吸收坠落的攀岩者的冲击力。静力绳的伸展性很小，使得它们在下降、上升或牵引重物等情况下非常有效。切勿使用静力绳进行顶绳攀登或者先锋攀登，因为其设计、测试或认证不适用于这些类型的负载。

如果你正在挑选一条攀岩的动力绳，你可以有三种选择：单绳、半绳和双绳。

动力绳单绳

它们最适合传统攀岩、竞技攀岩、大岩壁攀登和顶绳攀登。

从走天涯登山绳的销售情况来看，绝大多数登山者都购买动力绳单绳。“单绳”的名称表示绳索是为单根使用而设计的，而不是与其他绳索一起使用。

单绳有许多不同的直径和长度，使其适用于广泛的攀爬训练，并且它们通常比双绳索系统更容易操作。

一些单绳也被认证为半绳和双绳，允许你在三种攀岩技术中的任何一种中使用它们。重要的是只使用一根绳子，正如它被设计和测试的那样。

动力绳半绳

半绳最适合传统攀登中的游走型多段岩石路线、登山运动和攀冰。

用半绳攀岩时，需要同时用两根绳子。当你上升时，把一根绳子挂入左边的保护挂点，另一根绳子挂入在右边的保护挂点。如果操作正确，这将允许绳索平行和笔直运行，从而减少绳索在攀爬路线上的阻力。

与动力绳单绳相比，半绳有一些优缺点：

优点

• 半绳技术减少了攀爬路线上的绳索阻力。
• 当把两条绳子绑在一起下降的时候，能够达到单绳的两倍距离。
• 如果其中一根绳子在坠落过程中受损或被落石割伤，两根绳索能提供更多的可靠性。

缺点

• 与单绳相比，由于你用两条绳子攀爬和下降，半绳需要更多的技巧和精力来操作。
• 两条绳子的组合重量比一条绳子重。（不过，你可以将其中一根绳子交与你的攀爬伙伴来分担负载。）

半绳的设计和测试仅针对两根完全一样的绳索配对使用的情况；不要混用不同的尺寸或品牌。

一些半绳也被认证为双绳，允许你使用对应的技术操作它们。也有一些三重认证的登山绳，可作为半绳，双绳或者单绳，具有最大的通用性。需要的注意是必须按照设计和测试的方式来使用绳索。

动力绳双绳

双绳最适合传统攀登中非游走型多段岩石路线、登山和攀冰。

与半绳类似，双绳也是一个两根绳索组成的系统。然而，对于双绳，你总是将两股绳索挂入同一个保护点，就像用单绳一样。这意味着绳的阻力比半绳更大，这使得双绳成为非游走型路线的一个很好的选择。另一方面，双绳往往比半绳细一些，这使得整个系统更轻，体积更小。

双绳与单绳相比有许多优点和缺点，和半绳类似：

优点

• 当把两条绳子绑在一起下降的时候，能够达到单绳的两倍距离。
• 如果其中一根绳子在坠落过程中受损或被落石割伤，两根绳索能提供更多的可靠性。

缺点

• 与单绳相比，由于你用两条绳子攀爬和下降，半绳需要更多的技巧和精力来操作。
• 两条绳子的组合重量比一条绳子重。（不过，你可以将其中一根绳子交与你的攀爬伙伴来分担负载。）

静力绳最适合用于救援工作、探洞、上升下降、牵引负荷等。静力绳在你不想让绳索有太大延伸的情况下尤其有效，比如当你下放受伤的攀岩者、沿绳索上升或者用绳索把重物拉上来等情况。切勿使用静力绳进行顶绳攀登或先锋攀登，因为其设计、测试或认证不适用于这些有大的冲坠的情况。

登山绳的直径和长度

登山绳直径

一般来说，越细的绳子越轻。但是，细的绳子可能耐用稍差一点并且需要更多的技巧来安全地操作。越粗直径的绳索可以越耐磨，以便频繁使用。如果你在峭壁上使用绳子，你可能会想要一条更粗的绳子。如果你远足长途进行多段线路攀岩，你需要一条更细、更轻的绳子。

Single ropes up to 9.4mm: Ropes in this range are very lightweight, making them ideal for long multi-pitch climbs where weight is important. However, skinny single ropes are not rated to hold as many falls as thicker ropes, they are harder to handle and they tend to be less durable.

If you plan to do lots of top-roping or take repeated falls while figuring out the moves on a sport climb, choose a thicker rope.

Be aware that a skinny rope can move quickly through a belay device, so you need a very experienced and attentive belayer to climb with one.

9.5 – 9.9mm single ropes: A single rope in this range is good for all-around use, including trad and sport climbing. These ropes are light enough to take into the mountains yet durable enough for top-roping at the local crag. They’re generally more durable than very skinny ropes and they are easier to handle.

Single ropes 10mm and above: Ropes with a diameter of 10mm and above are best for gym climbing, frequent top roping, figuring out the moves on sport routes and big-wall climbing. These styles of climbing can wear out a rope faster so it’s wise to go with a thicker, more durable rope.

Half and twin ropes: Half ropes typically have a diameter of about 8 – 9mm, while twin ropes are usually about 7 – 8mm thick.

Static ropes: Static ropes have a diameter of 9 – 13mm, and are commonly measured in inches, so you may see the diameter stated as 7/16”, for example.

Climbing Rope Length

Dynamic ropes for rock climbing range in length from 30m to 80m. A 60m rope is the standard and will meet your needs most of the time.

Outdoor climbing ropes: When deciding what length to buy, remember that your rope needs to be long enough so that half its length is equal to or greater than the route or pitch you’ll be climbing.

For example, if a climbing route is 30m long, then you need at least a 60m rope to be able to climb up and be lowered back down off of an anchor at the top of the climb. Some modern sport-climbing routes require a 70m rope in order to lower to the ground.

Indoor climbing ropes: Shorter-length ropes, about 35m long, are commonly used for gym climbing because indoor routes tend to be shorter than outdoor routes. Again, be sure the length of rope is long enough to lower a climber.

Static ropes: Static ropes for rescue work, caving, climbing fixed lines with ascenders and hauling loads come in a variety of lengths and are sometimes sold by the foot so you can get the exact length you need.

If you’re unsure what length rope you need for a particular climbing area, it’s best to ask other climbers and consult a guidebook.

Climbing Rope Weight

The overall weight of a climbing rope is largely determined by the diameter and length. Generally, a skinnier rope will be lighter than a thicker rope, but core construction is a factor that can make a skinny rope heavier than a thick rope.

It’s standard for weight of dynamic climbing ropes to be listed as grams per meter (eg. 58 g/m), making it easy to compare rope weight regardless of the overall length. Use the grams per meter number and the length of a rope to calculate a rope’s overall weight.

Weight for static ropes is often given as weight per foot.

Climbing Rope Features

Look for these features when you are comparing climbing ropes. They can make a difference in performance and ease of use.

Dry Treatment: When a rope absorbs water, it gets heavier and is less able to withstand forces generated in a fall (the rope will regain all of its strength when dry). When it’s cold enough for absorbed water to freeze, a rope gets stiff and unmanageable. To combat this, some ropes include a dry treatment that reduces water absorption.

Dry-treated ropes are more expensive than non-dry-treated ropes so consider whether or not you need dry treatment. If you primarily sport climb, a non-dry rope is probably sufficient since most sport climbers will pull their ropes and go home when it rains. If you will be ice climbing, mountaineering or multi-pitch trad climbing, you will encounter rain, snow or ice at some point, so choose a dry-treated rope.

Dry ropes can have a dry core, a dry sheath or both. Ropes with both offer the greatest moisture protection.

Middle mark: Most ropes include a middle mark, often black dye, to help you identify the middle of the rope. Being able to identify the middle of your rope is essential when rappelling.

Bicolor: Some ropes are bicolor, which means they have a change in weave pattern that clearly differentiates the two halves of the rope and creates a permanent, easy-to-identify middle mark. This is a more effective (if more expensive) way to mark the middle of a rope than black dye because dye can fade and become difficult to see.

End warning marks: Some ropes include thread or black dye showing that you are coming to the end of the rope. This is helpful when you’re rappelling or lowering a climber.

Climbing Rope UIAA Safety Ratings

The Union Internationale des Associations d’Alpinisme (UIAA) is the international mountaineering and climbing federation that creates safety standards to which all climbing ropes must adhere. Independent labs are responsible for carrying out the tests. All dynamic ropes carried by REI pass the UIAA tests.

The packaging on dynamic climbing ropes lists the test results for UIAA safety standards, including fall rating, static elongation, dynamic elongation and impact force. Looking at these ratings while thinking about what type of climbing you will be doing can help you choose a rope.

Fall Rating

The UIAA tests ropes to see how many falls they can hold before failing. Lab falls create much greater force than most real-world climbing falls. Therefore, the fall rating is mostly a comparative value.

Single ropes are tested by dropping an 80kg weight onto the rope, half ropes are tested by dropping a 55kg weight on a single strand, and twin ropes are tested by dropping an 80kg weight on 2 strands. All single ropes and half ropes must withstand a minimum of 5 UIAA falls. Twin ropes must withstand a minimum of 12 UIAA falls.

All ropes that meet the UIAA fall rating standard are safe for climbing. A rope with a higher fall rating may mean that that rope will last longer than a rope with a lower rating. However, always inspect your rope closely after a severe fall and consider retiring it if any damage is detected.

Static Elongation

Static elongation, also called working elongation, is the amount that a dynamic rope stretches with an 80kg weight hanging from it. Elongation on single and twin ropes cannot exceed 10 percent of the total rope length and half ropes cannot exceed 12 percent.

Static elongation is important to consider when top-rope climbing, hauling gear and climbing fixed ropes with ascenders. Higher static elongation generally indicates less efficiency because energy is wasted through rope stretch.

Dynamic Elongation 

Dynamic elongation is the distance the rope stretches during the first UIAA fall. Higher elongation equals a longer fall, so generally speaking, a lower number is better because less stretch may prevent a falling climber from hitting a ledge or the ground. However, less dynamic elongation means a higher impact force on the climber, belayer and gear. The UIAA allows ropes to stretch no more than 40 percent of the length of the entire rope. 

Impact Force 

Impact force is the amount of force in kilonewtons that is put on the falling weight during the first UIAA fall. A lower number indicates less force on the falling climber, the belayer and the gear. The higher the dynamic elongation, the lower the impact force.

Lower impact forces make for a soft landing on the rope when you fall, but with that usually comes greater stretch, which can be less efficient when top roping.