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Gear and Carabiners

The Accessories You Need to Climb Effectively:


Harnesses make hanging from the rope comfortable by distributing your weight over a larger surface area, reducing the pressure where it contacts you.

pressure = force area

Minimum Comfort:

This minimalist harness is designed for alpine climbers who are willing to sacrifice comfort for lightweight. Its thin waist belt and leg loops make it less comfortable to hang in than bulkier harnesses.
Straps on minimum comfort harnesses are a lot slimmer and lightweight looking with fewer buckles.  

Maximum Comfort:

This harness is made for big-wall climbers who often spend days or weeks hanging in their harness.The thick waist belt and leg loops make it very comfortable to hang in.

Bulky, heavier looking harness with a thick waist belt and leg loop for maximum comfort.


Figure 42: Chemical structure of chalk
Chemical structure of Magnesium Carbonate (MgCO3), or chalk and its relationship between Magnesium, Carbon and oxygen that make up chalk.

Chalk is the chemical magnesium carbonate (MgCO3). Climbers often apply it to their hands to keep them dry so that they can grip the rock. Chalk can absorb the sweat your hands create, keeping them dry and maintaining good friction with the rock.





Climbing shoes are designed to give climbers an advantage. The rubber on the soles and around the toes is specially formulated to increase the coefficient of friction (μs) between the rock and shoes.

F = μ s × N
Figure 43: Diagram showing the friction force between rock and shoe.
The rubber on the soles and around the toes increase the coefficient of friction between rock and shoes. Increases in frictional force helps the climber stand on his feet and remove weight from his hands.

Note: Increasing μ s increases the frictional force that helps the climber stand on his feet and remove weight from his hands.


Carabiners are a simple and convenient means of attaching ropes, slings and other pieces of equipment to each other.

Parts of a Carabiner

Figure 44: Carabiner showing that Major Axis = 22 kN; Minor Axis =7 kN; Open Gate = 5kN
A carabiner is a D-shaped or oblong metal ring with one spring hinged side (gate) and where it connects to (the nose). The spine of a carabiner will usually show the kN rating engraved suitable for rock climbing.

Strength Ratings

Most carabiners are stamped with strength ratings that designate Major Axis, Minor Axis and Open Gate strengths.

Major Axis = 22 kN

Major axis carabiners are loaded going lengthwise and are the strongest orientation.

Minor Axis = 7 kN

  Minor axis carabiners are loaded going sideways.

Open Gate = 5 kN

Open Gate carabiners are loaded while open.  

Why the Notch?

Carabiners have a notch or similar feature at the nose to distribute some of the load across the gate. This makes carabiners inherently stronger and allows manufacturers to use less material.

Factory of Safety.

The ratio that describes how much stronger a part or a system is than what it actually needs to be for its intended application.

Factory of Safety show that the minor axis is 20 kN while the Major Axis is 5kN (an average lead climbing fall). Minor Axis: 20 kN
Major Axis: 5 kN (an average lead climbing fall)
FoS = breaking   load applied   load FoS = 20 kN 5 kN = 4

Most climbing carabiners have a strength above 20 kN. Theoretically, this means they are strong enough to support a full-size pickup truck, even though forces of that magnitude are almost unattainable while climbing.

Figure 45: A truck being supported by a single carabiner that has a minor axis strength of 22kN making it able to be supported.
truck being supported by a single carabiner

= 22 kN
~ 4,945 pounds
Curb Weight: 4,930 pounds

= 22 kN
~4,945 lb
Curb Weight = 4,930 lb
FoS = 4 , 945   lb 4 , 039 = 1 . 2  

With a safety factor barely larger than 1, if a small amount of weight were added to the truck the carabiner would break.