6 MM DYNEEMA BREAKING STRENGTH 12.38 kN
A thin 6 mm rope that holds more than 1200 kilograms before breaking. This is what the test shows.
This 6 mm Dyneema rope with polyester sheath breaks at an average of 12.38 kN, equivalent to 1262 kg.
Thin rope is often seen as weak rope. That's not the case with this 6 mm Dyneema rope. It holds an average of 1262 kg before breaking, more than double what you'd expect for this size. The SK78 fiber core makes the difference.
The five measurements are close together: from 11.78 kN to 12.77 kN, a spread of only 0.99 kN. That's a good sign. It means you can rely on a predictable breaking strength, not a guess.
6 mm Dyneema SK78 with polyester sheath: material and construction
This rope has a core-with-sheath construction. The core consists of a single braided bundle of white SK78 fibers, a type of Dyneema. The sheath is made of polyester and protects the core against wear.
Dyneema is an HMPE fiber: a synthetic fiber with very high strength per kilogram of weight. It floats on water and does not absorb water, so it holds the same strength wet as dry.
How we test
The breaking strength tests are carried out in-house by Otto Tromm on a universal testing machine with a capacity of 50 kN. Two sets of specially developed rope clamps are used for this machine, depending on the diameter and material of the rope. These clamps allow rope to be tested without first being spliced.
All tests are carried out according to the ISO 2307:2019 guidelines. This includes testing 5 times and using a test speed of 20 mm per minute. Each rope is secured so that it is taut. No pre-tension is applied, since elongation is not measured in these tests.
Two repetitions of each test are filmed with a Sony camera on a tripod. The exact progression of the graph is also recorded separately on video.
This allows the tension curve and breaking behavior to be matched exactly with the graph from the breaking strength testing machine.
For each of the 5 tests, the tester also records written observations, capturing details such as the degree of elongation, the way the rope breaks, and the loudness of the snap when the rope breaks.
Breaking strength test results
Five measurements, all close together. The lowest measurement was 11.78 kN, the highest 12.77 kN. That difference of 0.99 kN is small for a rope of this type.
The rope always broke in two stages. First the core breaks, then the sheath. Only in the fifth test did the sheath remain intact after the core broke. A light snapping of strands could be heard before the core broke.
The rope broke in two phases: first the core, then the sheath. Keep this in mind when interpreting the figures.
How does this rope compare to other 6 mm ropes
Compared to nylon and polypropylene of the same diameter, this Dyneema rope stands out. The differences in kN show the impact of fiber type.
The nylon core-sheath rope achieves 6.75 kN, the polypropylene variants 6.73 kN and 6.58 kN. The Dyneema rope achieves almost double: 12.38 kN. At the same diameter, fiber type makes the biggest difference, not construction.
When to use this rope
The high breaking strength at a small size makes this rope suitable for applications where weight and thickness matter.
✓ Suitable
- Lightweight attachment lines — high breaking strength with low weight and small size
- Applications on or near water — Dyneema doesn't absorb water and floats
- Work with UV exposure — the fiber is UV-resistant
- Situations requiring thin rope with high strength — 12.38 kN in 6 mm
✕ Not suitable
- Shock loading — Dyneema stretches less than 4% and does not absorb shocks well
- Prolonged static loading at temperatures above 60°C — the fiber can permanently stretch (creep)
- Applications requiring high elongation — nylon is more suitable for this
Alternatives to consider
Conclusion: is this Dyneema rope the right choice
This 6 mm Dyneema rope achieves an average breaking strength of 12.38 kN, with a small spread between measurements. This makes it a reliable choice for lightweight applications that must withstand high loads, such as attachment lines on or near water. For shock loading or situations requiring high elongation, this rope is not the right choice: choose nylon instead.
Otto Tromm tested this rope five times and heard the same soft snap five times before the core gave way. He now calls it the sound of money doing its job.
