Calculate belt drive speed ratio, driven RPM, belt length, and belt speed from pulley diameters.
Belt speed is typically limited to 25-30 m/s for V-belts and up to 50 m/s for flat belts. Exceeding these limits causes excessive heat, vibration, and premature wear. Synchronous (timing) belts can run faster.
The formula gives a close approximation for open belt drives. For crossed belts, the formula differs. Always round up to the nearest standard belt size and verify with the manufacturer's catalog.