Researchers investigated the influence of the weft insertion processing technique for warp knit fabrics, binding yarn, and the loop system on the performance of polypropylene (PP) glass fiber reinforced composites. A Twintex yarn commingling machine manufactured the uniaxial preforms from glass and PP filaments with a glass fiber volume of 50 percent. A Malimo 14022 knitting machine used the Karl Mayer magazine weft insertion technique to manufacture the warp knit composite fabrics. Tests included tensile, three point bending, impact bending, and shear tests. Scanning electron microscopy analyzed the fracture surfaces after in-plane compression shear loading. Results revealed that mechanical properties depended on the type of binding yarn and stitching length. In addition, curvature of the reinforcing fibers was responsible for crack initiation. 4 refs.