Stop guessingyour string.

String bed stiffness, measured in lb/in, describes how much the string bed deflects on impact. Stiffer strings (higher numbers, typically 200+ lb/in) deform less, giving a more controlled, lower-powered response but transmitting more shock to the arm. Softer strings (under 150 lb/in) deflect more, playing more comfortably and with more built-in power.

Natural gut and premium multifilament nylon strings typically lose the least tension, often 15 to 25 lb under the test protocol. Polyester strings lose the most, commonly 30 to 50 lb, which is why polyester setups need restringing more frequently even though the string has not broken.

Spin potential is the ratio of string-on-ball friction to string-on-string friction. A string that grips the ball firmly but slides easily against its neighbours snaps back into place at impact, brushing the ball and generating more spin. Higher ratios indicate more spin potential.

StringSpec compares up to three strings side by side. Each metric is shown with the leading string marked, so you can see instantly which setup is softer, livelier, holds tension longer or generates more spin.