Spec Clutch ST654 Stage 4 Performance Clutch Kit - Carbon Semi-Metallic Puck Disc

The Spec Clutch ST654 Stage 4 Clutch Kit is a high-performance, solid hub clutch system engineered for heavily modified engines and demanding motorsport applications. Built as the solid hub evolution of the Stage 3, this kit delivers aggressive, instantaneous engagement and reduced rotating mass — making it the go-to choice for drivers who need maximum power transfer over street comfort.

The Stage 4 features a solid 8-rivet hub with a heat-treated carrier assembly for exceptional strength and durability under extreme load. Available in 3, 4, or 6-puck carbon semi-metallic configurations, it can be tailored to your specific performance needs: choose the 3-puck for the lightest possible setup, the 6-puck for the smoothest engagement among the puck options, or the 4-puck as a balanced compromise between the two. While the 6-puck configuration is technically street drivable, the rigid hub design makes this kit best suited for dedicated race and competition use.

Key Features:

• Solid 8-rivet hub construction for maximum torque transfer
• Heat-treated hub and carrier assembly for long-term durability
• High clamp performance pressure plate
• Carbon semi-metallic friction material in 3, 4, or 6-puck configurations
• Lightweight design reduces rotating mass for faster throttle response
• Includes bearing and installation tool kit

Recommended Driving Disciplines:

• Drag Racing
• Road Racing
• Drift
• Rallye
• Pulling
• Circle Track

Note: The Stage 4 is not recommended for street use due to its rigid hub and aggressive engagement characteristics. Prior to installation, the existing flywheel must be resurfaced or replaced with a new SPEC flywheel to ensure proper friction surface integrity.