March 7, 2015

Used Rock climbing shoes

	ALTHOUGH IT IS POSSIBLE to climb rock without equipment, it is difficult to do so safely. All of the equipment discussed in this chapter is exclusively for safety, except for shoes. Climbing shoes enhance climbing ability much like running shoes enhance running ability. The following sections discuss climbing shoes, rope, general-purpose devices for connecting things, nylon cord, harnesses for connecting climbers to things, devices for applying friction to the rope, and devices for wedging into the rock.
Shoes	The most useful piece of climbing equipment is a pair of climbing shoes. Improvements in shoe design alone have allowed climbers to climb many things previously unclimbable. The modern climbing shoe has a stiff, smooth rubber sole that protects the foot from sharp, rough rock, and provides more friction than a bare foot. A pair costs between $100 and $150. Climbing shoes fit tightly to prevent the foot from sliding around within. This makes them uncomfortable, but the improved friction and control they afford far outweigh the discomfort.
Rope	A modern climbing rope, a key piece of safety equipment, is of kernmantle construction, consisting of continuous braided nylon fibers, the kern, surrounded by a continuous braided nylon outer sheath, the mantle. Such construction is superior to the more traditional laid rope (three large strands twisted together) because the outer sheath protects the inner core, where most of the strength lies, from the elements. Climbing rope is dynamic: able to stretch a bit under tension. This is because the rope must stop falling climbers. If the rope did not stretch, a falling climber would be jerked suddenly as the rope stops him. Instead, the rope slows his fall more gently. Climbing ropes are usually ten to eleven millimeters in diameter and fifty meters (about 165 feet) long. Such ropes cost between $100 and $180.
Carabiners	Carabiners, used constantly in climbing, are rings of solid aluminum with a spring-loaded gate that allows them to be opened. Normally, the spring holds the gate closed, but the gate can be opened to admit a rope. Carabiners are inexpensive (between $5 and $20), strong (most are rated to hold at least 20 kN, about 2.2 tons), and versatile. Virtually every climbing technique uses carabiners. There are many variations on the basic carabiner design. The carabiner shown above is a ``D'' because the ends have an asymmetric shape that tends to push the rope against the solid side, away from the weaker gate side. An older variant (below left), the oval, has no such asymmetry, and is not as strong. Another variant, the bent-gate (below right), has a curved gate that makes inserting a rope easier. However, the bent gate also makes it easier for the gate to work itself open, making it less safe than other varieties. A carabiner is safe until its gate opens. To increase security, two carabiners can be used in tandem with their gates reversed (i.e., opening in opposite directions). It is less likely that something would cause both gates to open at once. An alternative to a pair of carabiners, the locking carabiner (shown above) has an additional mechanism that makes it harder for the gate to open accidentally: a sheath that covers the gate and the outer C-shaped portion of the carabiner. This sheath either screws into place, or uses a spring to hold it in place. Each variety is well-suited to certain applications. The ``D'' is the most versatile, although it must sometimes be used in pairs for added security. The oval is used where its symmetry is desirable, typically on longer routes. The bent-gate is excellent for rapidly securing the rope, although it is slightly less safe. Locking carabiners are best when taking the extra time to attach them is not a problem.
Webbing	Tubular nylon webbing is used frequently in climbing. It is made of nylon woven into a flat tube an inch across. It is very strong (its tensile strength is about 18 kN, about 2 tons) and inexpensive-about $0.25 a foot. Unlike climbing rope, it does not stretch under tension. If not expected to stop a long fall (and it is never used in a situation where it is), this is preferable. Nylon webbing is most often used tied into a a loop. Climbing stores sell it by the foot, and it can be easily cut to any desired length. The ends are cauterized with heat to prevent fraying. Also popular is pre-sewn webbing-loops of webbing sewn (as opposed to tied) together at the factory. Pre-sewn webbing is more expensive, more convenient (since there is no knot), and may be safer, but custom-tied loops are cheaper and adjustable.
Harnesses	To attach herself to a rope, a climber uses a sewn harness. A typical one has a wide nylon belt for the waist and a pair of leg loops for the...