Stiffness, elasticity, modulus and work-to-break

Often the ratio of bundle tenacity to bundle elongation is taken as a measure of stiffness. Stiffer fibres are less likely to buckle or entangle, and form fewer neps during carding. A better measure of stiffness would be the ratio between absolute fibre strength (cN) and elongation, as this would allow for the substantial effect of fibre fineness on stiffness and nep formation.

Work-to-break, elasticity and modulus can be estimated from high volume measured results, but the magnitude and importance of variations in these properties in practice still need to be established. These properties are determined by both genetic and environmental factors.