How to Choose A Climbing Rope
Climbing ropes are the strand that links together the entire safety chain, and the thread that saves your life when you fall. With so much riding on this piece of equipment, it's clearly important to choose the most appropriate one for the kind of climbing you're doing. There is a huge variety of different ropes to choose from and a lot of questions to answer. Single or double? Dry treated? What length? This buying guide will help you find the answers.
Every climbing rope is rigorously tested and must meet certain standards, for instance on the impact force it transfers and the number of falls it will take.
Types of Climbing Rope
Climbing ropes stretch dynamically to absorb the energy generated by a falling climber. It's very important to make sure you buy a dynamic climbing rope as static ropes will not absorb energy and therefore leave your body to take the full force of the fall.
Single ropes are suitable to be used on their own. They are strong and simple to use for both lead climber and belayer. Single ropes are ideal when the route follows a fairly straight line, so choose one for sport climbing, indoor walls (leading or top-roping) and short straight-up trad climbs.
Diameters now range from 8.7mm to 11mm. Thicker diameters will usually absorb more falls and are likely to last longer. They are also easier to use in a traditional belay plate thanks to increased levels of friction. Single ropes below 10mm are lighter weight, have less rope drag and are slicker to use but should be belayed with caution.
Half (Double) Ropes
Traditionally protected climbs often wander across an expanse of rock or mountainside. Opportunities for protection might not be in a straight line above you. Using a pair of half ropes you can keep each rope running in a straight line, clipping them independently to left and right and thus avoiding the 'zig-zag' effect (and rope drag) you'd get with a single rope. Another benefit is the ability to knot the ropes together and abseil full rope length distances.
Diameters range from about 7.5mm to 9mm. The "industry standard" is around 8.5mm as this offers a great combination of durability, fall resistance and handling.
Here the climber uses two very thin (<8mm) ropes which must both be clipped together to the same protection. Effectively they should be used together like a single rope, with the main benefits being a slight weight reduction compared to half ropes and the ability to do full rope-length abseils compared to single ropes. Twin ropes are very rarely used in the UK.
A fourth category is the walker's confidence rope. This is a thin rope suitable for use by walk leaders when short-roping nervous members of the party over steep or rocky ground. It is not suitable for rock climbing.
Triple Rated Ropes
A few special ropes (like the Mammut Serenity 8.7 out in Spring 2013) are triple rated for use as a single, half or twin rope. These represent the cutting edge of technology. Super lightweight and versatile, you could use it for a sport climbing redpoint one day and then pair it with a similar diameter half rope for trad climbing the next. On trad climbs you have the confidence of knowing that one of the pair is rated as a full single rope, also a blessing for glacier travel and alpine routes.
The main disadvantage is durability. The skinniest ropes inevitably have a lower percentage of sheath and should only be used for onsight or redpoint climbs rather than working sport routes.
Ropes perform very differently when wet. Moisture shortens nylon fibres and can cause around 10% rope shrinkage. This in turn affects its dynamic properties – it won't stretch as much when taking a fall so the impact force will be higher. Ropes also swell which increases friction over rock and runners, in turn raising the potential fall factor. The worst case scenario (often encountered in Scottish winter conditions) is when a wet rope freezes and becomes totally unmanageable.
For many people this won't be a problem – fewer people go climbing when it's raining! But we live in a wet country and it pays to be prepared. For winter climbing a dry treatment really is essential.
Do be careful when choosing between dry treated ropes. A basic dry treatment might be a water repellent coating applied to the outside of a rope, which will wear off eventually (and perhaps sooner rather than later). The best dry treatments seal both the core and the sheath. Beal is one brand that treats every millimetre of filament and heats it to fix the treatment before their "Golden Dry" ropes are even made. This kind of treatment is more effective and lasts the lifetime of the rope.
Choosing a Climbing Rope Length
The length you choose depends on the kind of climbing you're doing:
Indoor Climbing Rope Length
Many indoor climbing centres have leading walls between 10 and 15m high. For this reason you need a minimum of 30m rope. If you're buying a new single rope specifically to use indoors, a 30m or 40m should be ideal. Anything longer will just mean you spend longer pulling the rope through, untangling coils and recoiling with leaden arms at the end of the session!
Sport Climbing Rope Length
Many outdoor routes are significantly longer than those found indoors and it's worthwhile having more than enough rope for any given route – you don't want to be left dangling a few feet above the ground when being lowered off a climb. 50m should be considered a minimum; 60m will cover most situations; 70m is a great idea particularly for the big continental pitches; and 80m will allow you to do the biggest extensions.
Trad Climbing Rope Length
The main two lengths used for trad climbing are 50m and 60m half ropes. The shorter 50m length will often be fine for rock routes, particularly single pitch. They save weight and reduce rope faff! However 60m lengths give you greater freedom to push on to better belay stances, and more rope to use if attaching direct to the belay with clove hitches. 60m half ropes also allow longer abseils which can be crucial on winter and alpine climbs.
Ropes Technical Guide
Take a look at the packaging of any rope and you'll see an array of stats such as Impact Force, Number of Falls, Sheath Percentage and Weight per Metre. These figures are a good indicator of performance. This quick guide will explain the different terms and why they're important.
What is a Climbing Rope's Fall Factor?
Before looking at the figures quoted on rope technical notices it helps to understand the concept of fall factors. This is a measure of the hardness of a fall. The scale runs from 0 to 2; the higher the fall factor, the harder the fall. The calculation is:
Distance fallen / Length of rope between belay plate and climber = Fall Factor
As an example, imagine a climber gets to 4m above a belay, with no protection clipped. If they fall they will end up 4m below the belay, a total drop of 8m on 4m of rope.
8m distance / 4m rope = fall factor 2
If the same climber had clipped a bolt at 3m he would only fall a total of 2m with 4m of rope out.
2m distance / 4m rope = fall factor 0.5
The second scenario results in a much softer, safer fall and is a good reason to place some protection as soon as possible after leaving a belay on multi-pitch routes. It's worth noting that factor 2 falls are a theoretical upper limit but in reality rope stretch, friction and the body combine to absorb some energy and reduce the overall fall factor. Indoors the maximum theoretical fall factor is only 1, because it is impossible to fall past your belayer (who's stood on the floor).
This is the force felt by a climber as the rope comes tight at the end of a fall. Ropes with a low Impact Force absorb more energy, dynamically reducing the force you (and the whole system) feel and therefore mitigating higher fall factors. A rope's specified impact force is calculated in a lab and varies according to the type of rope.
Single ropes must have an impact force lower than 12kN holding the first factor 1.77 fall with a mass of 80kg.
Double ropes must have an impact force lower than 8kN holding the first factor 1.77 fall with a mass of 55kg.
Twin ropes must have an impact force lower than 12kN holding the first factor 1.77 fall with a mass of 80kg on two strands.
Number of Falls
The number of falls is a useful indicator of the potential lifespan of a climbing rope. The test requires successive factor 1.77 falls which (hopefully) are heavier than the vast majority of real world falls you will ever take. A higher figure shows an ability to recover from successive falls, retaining its dynamic properties for longer.
Single ropes should withstand 5 successive factor 1.77 falls with a mass of 80kg.
Double ropes should withstand 5 successive factor 1.77 falls with a mass of 55kg.
Twin ropes should withstand 12 successive factor 1.77 falls with a mass of 80kg.
Increasing the number of internal cables will increase the number of falls a rope can take (ideal for outdoors climbing). By contrast a rope with fewer cables but a thicker proportion of sheath will be more durable (ideal for indoors climbing).
Modern climbing ropes are universally of 'Kernmantle' construction. Here there is a core ('Kern') of cables twisted together and covered by a tightly woven sheath ('mantle'). The core does the hard work and the sheath protects it.
It is possible to vary the relative size of core and sheath to achieve different performance characteristics. For any given diameter of rope, those with a thicker sheath will be more durable while those with a lower percentage of sheath will give better dynamic performance.
Weight per Metre
Thinner ropes are lighter and so easier to climb with. A lower diameter means the rope rubs a thinner surface area against the rock or over karabiners, so you will experience less rope drag. For a climb at the edge of your capabilities any weight saving could make all the difference to success or failure, or make any climb seem that bit easier. The downside is that a thin rope's lifespan might be shorter than a thicker rope.
View our full range of ropes here.