The requirements in terms of wearing comfort with sportswear underwear and outerwear are widely linked to the use of elastane fibers. Today, elastomeric plated jersey fabric is one of the most common fabrics produced with large-diameter circular knitting machine (LCKM). However, the relation between elastane proportion and fabric characteristics has not been enough studied in literature and knitters generally use experience during machines adjustments in to order reach needed fabric characteristics. The aim of this paper was to investigate the relation between Lycra ® consumption and fabric dimensional and elastic behavior. The obtained results showed that Lycra ® proportion inside fabric has an incidence on fabric width, weight and elasticity. The origin of this behaviour has been discussed.