What Fiber for a Friction Hitch?

Nylon: Nylon is a strong synthetic fiber that is very stretchy and quite strong. Climbers have used small nylon cord of Kernmantle construction for friction hitches for a long time. Nylon has a melting-point of about 220 degrees centigrade (there is variation among different nylon sub-types.) When used for ascending ropes, backing up rappells, and progress-capture jobs I have never seen these melt; but I have when they are used to catch a significant fall, or when holding the high loads of a highline. Nylon tends to have a long service-life, because it has excellent flex-fatigue, and you can reasonably infer how much strength it has lost by inspection i.e. how many of the fibers are broken. I don’t make any hitch cords from nylon because I do not see advantages over polyester, and it is not available in as many types and diameters of cord. 

Polyester: Polyester is similar to nylon but a bit less stretchy and a bit more heat resistant, its melting point is  250-260 degrees centigrade. Used for ascending ropes, backing up rappells, and progress-capture jobs I have never seen these melt, but I have when they are used to catch a significant fall or when holding the high loads of a highline. Polyester tends to have a long service-life, because it has excellent flex-fatigue, and you can reasonably infer how much strength it has lost by inspection i.e. how many of the fibers are broken. I use polyester for many products primarily because it is available in many types of cordage in many diameters. 

Vectran: Vectran is unique among high-tenacity fibers, being a liquid-crystal-polymer, which means officially your ropes are actually liquid all the time! In practice, it is much stronger than nylon and polyester, very hard to cut, and more heat-resistant (melting point of 330 degrees centigrade.) It has a similar amount of friction to polyester. It has been used a lot in sailing applications and in some arborists' hitch-cords. Sources vary on how well it holds up to abrasion, what I have seen so far with hitch-cords is that it lasts longer than technora, but not as long as polyester. It wears out by getting fuzzy, and it is reasonable to inspect it and infer its strength by looking at how many fibers are broken. This “inspectability” is why I started making products from it. 

Technora: Technora is very popular for hitch cords because it won’t melt. At about 500 degrees centigrade it will start to burn instead. This is an advantage if you want to use your friction hitch to catch a large fall, or use it as your sole friction device to rappel. It has very high strength and cut-resistance, similar to vectran. The disadvantage is that it wears out quickly, and it weakens more than other fibers simply from being bent back-and-forth. Some testers have found that it can look barely worn and have lost its strength from flex-fatigue. It starts to get fuzzy right away with use, and makers of ropes that use a mixture of technora and other fibers find that it wears out the most quickly of all the fibers in the rope. I make a Technora Hitch Cord that is very strong when it is new, and works really well, but it does wear out quickly. 

Dyneema/UMPE: Dyneema is super strong and super light, which makes it wonderful for many applications. It is also super slippery and melts at about 150 degrees centigrade. It is weird stuff to try and use as a friction-hitch. Many people shy away from it because it seems likely to melt on you, and others claim because it is so slippery it doesn’t create enough heat to melt. I haven’t found an application for it,  and at this time I don’t make any friction hitch cords from it.