Bicolor and Bipattern Bumps

Explained Jul 5th 2017
  • Bicolor and Bipattern Bumps

It’s important to know where the middle of the rope is on a climbing rope, and the best way to determine the middle is to use a bicolor or bipattern rope. Sterling uses two different techniques for altering the sheath pattern on climbing ropes. The first is the bi-color. With bi-color ropes we strategically swap the colors on a few strands to make the two halves of the rope distinctly different. We achieve this by utilizing what is known as an air splicer (also known as an intermingling device or air entanglement device). Air splicing is a common method of joining two strands of multi-filament yarn throughout the textile industry. It is carried out by overlapping the two strands to be joined, placing them in the device, and then with a burst of compressed air the filaments are intermingled. The splice is then trimmed to remove any excess filaments protruding from the splice. The splice is very strong but because where the two strands overlap is thicker than the rest of the yarn. This produces small lumps in the sheath of the rope that can appear to be defects but are, in fact, just the spots where the two different color strands are joined.

  • Air splicer we use at Sterling
  • 2 strands of nylon fibers to be joined together
  • 2 strands joined with tails
  • A closeup of 2 strands joined with tails
  • Two strands spliced and trimmed
  • A hank of NanoIX purple bicolor featuring the bicolor changeover
  • A closer view of the spice within the sheath of the Nano IX purple bicolor
  • A close up view of the Nano IX bicolor sheath where the bumps from the air splice occur

The second method Sterling uses is the bi-pattern. In this method, we actually alter the pattern in the sheath without any splicing taking place. We do this by moving bobbins around the braiding machine in such a way as to change from spiraling stripes to a scattered speckle pattern. At the point where the change occurs the normal path of the changed strands is altered but remains continuous. Where the pattern change occurs some small bumps may appear where the strands cross one another. This can appear to be a defect but is actually just a slight disruption in the path of the sheath yarn.

  • The bobbins get moved around on the braider to change from a speckled to stripe pattern in the Marathon Pro Orange Bipattern
  • A hank of Marathon Pro orange bipattern shows where the pattern changes in the middle
  • A closer view of the Marathon Pro sheath where the bipattern change occurs
  • A close up view of the bipattern changeover to see colors change at the bobbin-level

Your bicolor or bipattern rope may have a slight bump at the middle of the rope, but rest assured, the rope is just as strong as a rope with a middle mark. In fact, the bicolor or bipattern is better because it will last the lifetime of the rope, where some middle marks wear off or get very difficult to see. Just remember when you cut the end of your rope, be sure to cut both ends so the color or pattern change stays in the middle!

Sterling offers bicolor options in the Fusion and Evolution series. In the Marathon Series- the Marathon Pro is the only rope featuring a bipattern option. All single dynamic ropes (non bicolor or bipattern) come with a middle mark.