Climbing Ropes

Climbing Ropes

Ropes : Modern climbing ropes have a Kernmantle (“Core-Sheath”) construction consisting of an inner core with an outer protective sheath. The core or “Kern” consists of inter-twisted strands which take the load. This is surrounded by a tightly woven protective sheath or “Mantle”.

Ropes may be either Dynamic or Static/Semi-Static. Dynamic ropes can stretch under load so are able to absorb the shock of a climber’s fall and greatly reduce the risk of injury when falling. Static ropes are used for abseiling, canyoning and caving where it is preferable to have a rope that stays a constant length. While all climbing ropes are dynamic, they can be used in various ways.

Single Ropes

Single ropes are designed to be used alone. They are generally used for sport climbing, at climbing walls and for short trad climbs where all protection points are in a straight line. Single ropes are strong and having just one to deal with makes rope use simple for both the lead climber and belayer. Modern single ropes range in diameter from 8.7-11mm. Thicker ropes generally absorb more falls and last longer, as well as being easier to use in traditional belay plates due to the higher friction. If considering using a thin single rope, make sure that it matches your equipment, technique and experience.

Half Ropes

Half or “Double” ropes offer more protection on traditionally protected climbs that may traverse across the rock face or mountain. In this situation it may not be possible to insert protection in a straight vertical line for a single rope. However by using two half ropes independently you can keep each rope running straight, clipping them into separate runners. Ideally the two ropes are clipped into alternative runners, but in reality you may need to clip a number of runners into the same rope before using the other rope again: the idea is to avoid the ropes zig-zagging up the route. 
Half ropes offer several advantages. You can add more protection and it’s unlikely that both ropes would be cut by rock fall. It’s easier to protect both leader and second when traversing and rope drag is reduced. Should you need to abseil then you can descend twice as far with half ropes compared to a single rope.
Half ropes generally have a diameter of 7.5-9mm. The most common diameter is 8.5mm, which gives an optimum mix of fall resistance, ease of handling and durability.

Twin Ropes

Twin ropes are thin ropes that are designed to be used together, both being clipped into every runner to work effectively like a single rope. Generally 8mm diameter or less, they offer a slight weight advantage compared to half ropes, and can be used for full-length abseils compared to single ropes.

Walking Ropes

These are thinner ropes designed for helping walkers over steep or rocky ground. They are not designed for climbing.

Triple Rated Ropes
Some manufacturers are now making high tech ropes that are triple rated to be used as a single, half or twin rope. Offering low weight and superbly versatile, their main disadvantage is durability.

Which Length?
Which length rope you needs depends on what sort of climbing you’ll be doing.

Indoor Climbing
You’ll need a rope that is at least twice the height of the walls you’ll be climbing. For many centres with walls about 15m high a 40m rope should be fine. 

Sport Climbing

Most outdoor routes are longer and it’s better to have slightly too long a rope than find yourself hanging a few metres off the ground when being lowered off. You’ll need at least a 50m rope; 60m is good for most routes. If you’ll be climbing longer pitches then choose a 70m or even 80m rope – don’t forget you’ll need double the length of the route to lower back down.

Trad Climbing
Most half ropes are available in 50m or 60m lengths and these are good lengths for trad climbing. 50m is a good length for rock routes, while 60m offers more options on alpine and winter routes.

Rope Specifications – what they mean.
Take a look at the specs on all our rope pages. The information below explains what these terms mean.

UIAA Falls
The UIAA standard test measures the number for Factor 2 falls that a rope will survive using a 80kg weight for single ropes or a 50kg weight for half and twin ropes.

Fall Factor Calculation.

Fall Factor = Distance Fallen/Length of rope which holds it.

In theory the maximum Fall Factor is 2. This corresponds to a climber falling off and falling vertically twice the length of rope from the last runner or belay point.
For example a climber who climbs 4m above the last belay point then falls 8m: 
Fall Factor = 8/4 = 2
If the same climber had clipped into a runner at 2m then the fall would have only been a total of 4m giving a Fall Factor of 1:
Fall Factor = 4/4 = 1
Other factures should be taken into consideration when considering rope strength, and resistance to cutting and abrasion are at least as important.

Impact Force

This measures the force experienced by the climber as the rope stops stretching at the end of the fall. Measured in kilo-Newtons (kN), the lower the Impact Force the less force on the climber and on the belay points. Impact orce is measured in kN using a first fall factor of 1.77 and a specified weight, depending upon rope type. Impact force must be less than these values:

Single ropes: 12kN with 80kg mass.
Half ropes: 8kN with 55kg mass
Twin ropes: 12 kN with 80kg mass on two strands.

Impact force increases during the life of the rope and the number of falls sustained so is a major consideration when deciding when it’s time to replace your rope.

Number of Falls

This gives a good idea of the likely durability of a rope. These test counts the number of successive factor 1.77 falls. The higher the number the better the ability of the rope to recover from the fall and the longer it can maintain the dynamic properties needed to protect the climber.

The standards are as follows:
Single ropes: 5 falls with a mass of 80kg
Half ropes: 5 falls with a mass of 55kg
Twin ropes: 12 falls with a mass of 80kg on two strands

Sheath Percentage

For any given diameter of rope, the higher the % of the sheath then the more resistant the rope. Most ropes have 35-45% sheath, while ropes designed for high intensity use may have over 45% making then more durable stiffer and with reduced dynamic ratings. The dynamic performance or stretchiness can be varied by changing the relative thickness of the core and the sheath. For a given diameter rope, the thicker the sheath the more durable the rope, while the thinner the sheath the better the dynamic performance.

Sheath Slippage

Since the sheath and core are independent of each other, it is possible for the former to slip over the latter, for example when jumaring or abseiling. The standard UIAA test requires that a 2.2m length of rope has less than 20mm sheath slippage after being pulled through the test rig 5 times. On many ropes from serious brands slippage is zero.

Rope Treatments

Many ropes are given a water repellent treatment, essential for use on alpine and winter routes. Ropes that absorb water shrink, which affects the dynamic properties and usability.
The specific treatments vary from brand to brand. Some treatments involve only treating the surface of the rope while better treatments will protect both the sheath and the core. We specify the treatment applied to each rope.

We hope that this information is useful. Should you like any more details, or help in selecting which rope is best for your needs, then, please get in touch with, we’re here to help.

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