When sourcing flat belt pulleys, you must prioritize material integrity and dimensional accuracy. Key specs include the crown height (camber), which is essential for belt tracking; a slight taper prevents the belt from slipping off. Ensure the bore diameter and keyway dimensions match your motor shafts precisely. For high-speed applications, specify Static and Dynamic Balancing (G2.5 or G6.3 standards) to minimize vibration and extend bearing life. Common materials include Cast Iron (GG25) for general use, Steel for high-load, or Aluminum for weight-sensitive applications.