Scrap tires are transported to the feed port of the rough crusher, usually via a conveyor belt or other device.

Inside the primary crusher, scrap tires are exposed to mechanical cutting, tearing or shearing devices. These devices may be rotating blades, gears, or other forms of cutting tools that rotate or oscillate to cut or tear the tire into smaller pieces or fragments.

Inside the rough crusher, there may also be some separation devices used to separate different parts of the tire, such as steel belts, rubber and fiber materials. This helps improve the efficiency of subsequent processing steps and ensures that various materials can be recycled or disposed of appropriately.

The processed scrap tire pieces or fragments are discharged from the primary crusher and are usually sent to the next processing stage via a conveyor belt or other device.