Dimensionally stable polyester yarn and preparation thereof

A continuous spin-draw-winding process to prepare a drawn polyester yarn suitable for use in high-speed tires and run-flat tires having high energy to break in combination with a good dimensional stability, comprising extruding molten polyester through spinning holes in a spinneret to form a bundle of molten spun filaments, solidifying the spun filaments by a gaseous cooling medium, fixing the spinning speed of the solidified filaments at a first godet in the range of 4050 to 5000 m/min, drawing the solidified filaments to a winding speed in the range of 6800 to 8000 m/min to form drawn filaments. The drawn polyester yarn has a high amorphous orientation distribution, a high crystallinity and a coarse structure. Dipped cords comprising such polyester drawn yarns exhibit excellent dimensional stability at higher temperatures.