Properties of Slackline Webbing
Slackline webbing is made from different materials such as nylon, polyester and a few others. Each material is incredibly strong and knowing some basics (which we’re going to help you with) will help you understand their general characteristics. Most webbing manufacturers state the MBS of their webbing in either pound force (lbf) or Kilonewtons (kN.) Breaking strengths can range anywhere from 4,000 lbf (20 kN) to over 9,000 lbf (40 kN). Some manufacturers claim webbing strength of 15,000 lbf (67 kN) with high tech materials such as Vectran.
When deciding on how strong you want your webbing to be it helps to understand what you intend to use it for; primitive system, trickline, longline, rodeoline, highline, etc. Primitive systems do not need the strongest webbing on the market. Most manage just fine with basic tubular webbing which comes in around the 4,000 lbf mark. When getting into longlining and highlining we suggest using webbing that is at least rated to 6,500 lbf.
Stretch is another aspect to consider when selecting a webbing. Stretchier slacklines tend to be wobblier and have greater bounce, meaning you can play with the dynamics more than you can with a low stretch webbing. High stretch webbing also requires a longer tensioning system, whereas less stretchy lines are easy to rig and walk but result in less dynamics. Stretch is typically stated as the percentage of elongation at a certain tension. There is no standard among manufacturers what tension to measure stretch at, so it can be tricky to accurately compare across different manufacturers. Differences in stretch can be vary significantly. Tubular nylon webbing stretches to around 20% or more before failure where others can be around 6%. Low stretch webbing is generally easier to walk, yet harsh on the body in highlines. Be very careful with low-stretch webbing in highlines, as it does not absorb much of the impact during leash falls.
Weight plays a surprisingly important role in webbing selection. Heavier lines are generally more difficult to walk. When a wobble or misstep occurs you send more mass into motion down the entire line. More mass in movement translates to more powerful waves going away from you. And one of the first things you’re going to learn about longlining is; what goes out must come back. So whatever wave or pulse you send out, it’s going to come back at you and you’ll have to compensate for it. If you’re just getting into longlining and you want something easy to walk, heavy webbing is generally not a good choice. Heavy lines are, however, great training lines and can boost your ability level quite rapidly. Weight is usually declared by the manufacturer in g/m. Anything under 40 g/m is rather light and above 70 g/m it starts getting pretty heavy.