The GP4000 S II is versatile enough for race wheels or training wheels. The proven aspects of the 4000 S II remain unchanged and handmade in Germany of course. Vectran Breaker Vectran is a synthetically manufactured high-tech fiber from a natural model. Like spider silk, Vectran is a liquid-crystalline polymer (LCP). Vectran is spun from melted liquid polymer Vectra and processed further to a multi-strand thread.