Prussiks should be what fraction size of the diameter of the main line?

Prussiks should be what fraction size of the diameter of the main line?

• A. 2/3-3/4
• B. 1/2
• C. 1/3-1/2
• D. 3/4-1

Answer: (A)

Prusiks function by friction between the smaller-diameter cord and the main line. To grip securely when loaded but release smoothly when you back off, the Prusik should be sized roughly two-thirds to three-quarters the diameter of the main line. This range provides a reliable bite without being so large that it won’t grip properly. If the Prusik is much smaller (like half the main diameter), it can bite too aggressively and be hard to release; if it’s too close in size to the main line or larger, it won’t bite well and may slip. So the two-thirds to three-quarters range best balances bite and release.

Prusiks function by friction between the smaller-diameter cord and the main line. To grip securely when loaded but release smoothly when you back off, the Prusik should be sized roughly two-thirds to three-quarters the diameter of the main line. This range provides a reliable bite without being so large that it won’t grip properly. If the Prusik is much smaller (like half the main diameter), it can bite too aggressively and be hard to release; if it’s too close in size to the main line or larger, it won’t bite well and may slip. So the two-thirds to three-quarters range best balances bite and release.