Choosing A Climbing Rope

4) Static vs. Dynamic

Climbing ropes are designed to belay a leader, and for that reason they are dynamic - this means that they are designed to stretch under high load so as to absorb the shock force. This protects the leader, the belayer and the protection by reducing fall forces.

Static ropes are more durable and resistant to abrasion and cutting than are dynamic ropes, but they lack the necessary protection against shock loads produced in a leader fall. For that reason they are used only in situations where such shock loads would never occur: rappelling, canyoning, spelunking etc. Static ropes are often used to create or to extend top rope anchors, and they can be used to belay a climber in a "slingshot belay" context. They should NEVER be used to belay a lead climber.

5) Stiffness.

One of the things that climbers seem to be very particular about is how stiff a rope they like. There doesn't seem to be a lot of agreement about this. Basically individual climbers learn what they like. For mountaineering, where coils are often carried over the shoulder or in the hand while moving, a softer rope more readily accommodates twists and is therefore more manageable. Also if you use a munter hitch to belay, you will have less twisting problems with a soft rope than with a stiff one.

The UIAA also rates rope stiffness in a standardized test. They tie an overhand knot, weight the knot to a specific amount and then measure the size of the hole in the knot. The UIAA expresses their standard by saying that a rope must measure at or less than 1.10, but what that number means exactly I'm afraid I honestly can't tell you! Soft single ropes have a rating of around .75 "mystery units", while stiff ropes are up around 1.0.

6) Durability:

This quality is difficult to define or assess, since we don't really know how durable ropes are: we never use them until failure and we don't therefore know when they're really worn out. In practice, decisions about a rope's state tend to be based on how fuzzy they are. Fuzzy ropes impart more rope drag, absorb more water, and inspire less confidence. There does seem to be a relationship between stiffness and durability, where the stiffer the rope the more durable it is. But other factors besides stiffness also effect durability, for example single pick construction tends to "fuzz out" faster than double pick. It's also true that different manufacturers weave the sheath more or less tightly and this too can effect durability. This is a complicated factor, and unfortunately not really verifiable. If your concerns revolve around safety questions, then a general rule is that skinnier ropes basically will have less of a margin for abuse, wear and tear than fatter ropes. But this margin is very high in all new ropes. Ropes very rarely break other than from getting cut, and it's not clear how much more resistant to cutting newer ropes are than more "worn out" ropes.

7) Weight:

Weight is important in a number or different ways. Anytime you have to carry the rope very far, such as in the mountains, at altitude, it's certainly beneficial to carry less weight. Another time weight can be important is when you're trying to climb at your very limit. When people are trying a difficult red point they often choose a very light weight rope, while for working a route and learning the moves, they worry less about the weight.

Weight is expressed in grams per meter. These days light ropes weigh in at less than 60 grams while heavier ropes can be as much as 80 grams.

8) Diameter

Single ropes run from a narrow extreme of about 9.4mm to a thick end of the spectrum at 11mm, while half and twin ropes vary between barely over 8mm to around 9mm. The correlation between weight and diameter is a loose one. So if your concern is weight, look at weight, not diameter. Other factors such as stiffness, durability and number of test falls held are also only loosely correlated to diameter. So look for the individual features and properties you're after, and don't be locked into thinking that a particular diameter rope will necessarily have these features.

One property that is directly related to diameter however, is how hard or easy the rope is to grab, fatter ropes being easier to hold onto than skinny ones.