String stiffness

String stiffness affects how a string will feel. Depending on whom you talk to, stiffer strings are referred to as either “crisp” or “harsh” and softer strings are referred to as “comfortable” or “mushy.”

Usually strings rank as follows from lowest to highest stiffness: Gut, multifilament nylon, solid core nylon, polyester, aramid.

IMPORTANT: Stiffness is the single most important performance property of the string. You should rate this as your first or second priority on your desired features.

Most other properties are related to it. Typically, a softer string will have a lower impact force, lower peak impact tension, longer dwell time on strings, and more stringbed deflection. The opposite is true with stiffer strings — higher impact force, higher peak tension, shorter time on strings, less deflection.

Stiffness is determined by measuring the tension and elongation changes during impact. Stiffness is defined as the change in tension during impact divided by the change in elongation. Higher numbers are stiffer.