8 mm coloured cord may seem unremarkable. But what this rope does on the universal testing machine differs noticeably from what the material would lead you to expect — and that makes this test worth examining closely.
What is the breaking strength of 8 mm coloured cord made from PPMF?
In our test, this rope broke at an average of 8.51 kN (868 kg), measured over 5 repetitions.
That is considerably higher than the average of 5.69 kN we measure for 8.0 mm rope in general.
What type of rope is this?
This is an 8 mm coloured cord made from PPMF (polypropylene multifilament fibres).
The construction is a sheath-core design: two cores of loose fibres enclosed by a braided sheath. This structure combines a protective outer layer with a load-bearing inner structure.
Polypropylene fibre is the lightest synthetic rope material and floats on water.
It is widely used in non-safety-critical applications: marking, barriers, packaging, campsites, events, garden use, and decorative applications.
The colours also make this cord suitable for colour-coding in storage and logistics environments.
Sheath-core constructions have a higher efficiency than twisted rope: the braided sheath protects the core against abrasion and UV, while the core carries the majority of the tensile load.
Test methodology
The test was carried out on a universal testing machine with rope-specific clamps, suitable for measuring rope without splices.
The test speed was 20 mm/s, in line with common practice for rope with a diameter up to 12 mm. Five measurements were taken.
No pre-tension was applied.
All samples were tested in dry condition.
The results reflect the actual breaking strength of the rope as supplied, without knots or splices.
Tests are conducted following ISO 2307 where practically applicable.
Test results
The average breaking strength over 5 measurements was 8.51 kN (868 kg). The highest recorded value was 8.71 kN; the lowest was 8.14 kN.
The spread between the highest and lowest measurement is 0.57 kN, indicating a reasonably consistent construction.
A notable observation during testing: in several measurements, one or two minor breaks occurred first — audible as a snapping sound — with nothing visible on the outside of the rope.
This pattern has been observed previously in sheath-core rope and is characteristic of the construction: inner fibres or core elements can partially fail before the sheath or the rope as a whole reaches break point.
The final breaking strength is therefore the value at which the rope has failed completely, not the value at the first internal break.
This is relevant when the rope is used in applications where noise or minor shocks go unnoticed: the first internal break signals the eventual failure, but is not visible from the outside.
Comparison with ropes of similar diameter
How does the breaking strength of 8.51 kN compare to other ropes with an 8.0 mm diameter?
Below is an overview based on our own test data:
- polypropylene (8 mm): 10.57 kN
-
polyester sheath-core — 32-strand braided: 9.38 kN
The 8 mm PPMF coloured cord, at 8.51 kN, scores considerably higher than the general average breaking strength of 5.69 kN measured across all 8.0 mm ropes in our database.
It remains below polypropylene (10.57 kN) and polyester sheath-core (9.38 kN), but exceeds the lowest comparable product by more than 3 kN. T
hat is a difference of more than 58%.
When is this rope most suitable?
This rope is best suited to applications where colour-coding, visibility, or marking is the primary requirement, and where a breaking strength of approximately 8.5 kN is sufficient. Specifically:
- Barriers at events, campsites, or construction sites
- Colour-coded marking in storage or logistics environments
- Packaging and bundling of goods
- Decorative applications where some strength is also required
The sheath-core construction makes this rope more comfortable to handle than twisted rope of the same diameter, and the coloured sheath offers resistance to light weather conditions for short-term outdoor use.
Limitations
This rope is not suitable for the following situations:
- Extended outdoor use: polypropylene fibres have the lowest UV resistance of all synthetic rope materials. Prolonged exposure to sunlight causes significant degradation of the fibre bundle, reducing breaking strength. The rate of degradation depends on intensity and climate.
- Applications where internal damage must be detectable: as described in the test observations, internal breaks can occur without any visible sign on the outside of the rope. This rope is not suitable for situations where visual inspection is the only method of control.
- High temperatures: polypropylene fibre has a low melting point (approximately 160–165 °C). Contact with hot surfaces or frictional heat can rapidly reduce strength.
- Safety-critical applications: this rope has not been assessed or certified for lifting, climbing, or life-safety applications.
Alternatives
Where greater UV resistance or higher breaking strength is required at a comparable diameter, the following may be considered:
- Braided nylon (polyamide) (8 mm, price per metre, White) — nylon offers higher elongation (20–35% at break) and is suitable for shock-absorbing applications, but loses 10–15% of its strength when wet.
Conclusion
The 8 mm PPMF coloured cord delivers an average breaking strength of 8.51 kN (868 kg) — well above the average of 5.69 kN for 8.0 mm rope and notably strong for its category.
It is best suited to marking, barriers, packaging, and short-term outdoor use where both colour identification and strength are required.
Take into account the limited UV resistance for prolonged outdoor use, and the fact that internal breaks are not visible on the outside of the rope.
This test was carried out by Otto Tromm, who still cannot quite believe that a coloured cord managed to turn his averages spreadsheet upside down — 8.51 kN for a rope that simply looks cheerful is not normal.
The test data were collected by Prorope. This text was generated using AI on the basis of those data and has been verified for factual accuracy. Read how we test and publish →