Initial stages for the development of a new Trevira type which is characterized by a higher dimension stability and break strength for the application field of V-belt softcord will be shown, Yarns based on PEN were presented as alternative to the high modulus aramids for the application of noise reduced V-belts, Bi-component yarns (Heterofil) can make an important contribution due to a more environmentally friendly V-belt cord treatment, Furthermore the choice of suitable twist constructions and treatment conditions will be explained in detail.