Spec Clutch SMG004 Stage 4 Performance Clutch Kit - Carbon-Graphite Solid Hub

The SPEC SMG004 Stage 4 Clutch Kit is a high-performance, solid-hub clutch designed for drivers who demand maximum torque capacity and durability under demanding race conditions. Built as a solid-hub evolution of the Stage 3, this kit features an 8-rivet solid hub with a heat-treated disc assembly for exceptional strength and longevity.

The SMG004 is available in 3-puck, 4-puck, or 6-puck configurations, allowing drivers to dial in the right balance of weight, engagement feel, and holding power. The 3-puck setup offers the lightest rotating mass, while the 6-puck delivers the smoothest engagement of the three options. The 4-puck configuration strikes a balance between the two. Note that while the 6-puck version is technically street drivable, the rigid solid hub makes this kit best suited for dedicated race applications.

Key Features:

• Solid 8-rivet hub — heat-treated for high-torque strength and durability
• Carbon-graphite friction material — proven performance under race conditions
• High-clamp pressure plate — maximizes holding power beyond OEM levels
• Available in 3, 4, or 6-puck disc configurations — select the setup that matches your driving style
• Includes bearing and tool kit — everything needed for a complete installation
• Designed, hand-built, and tested in the USA

The Stage 4 is ideally suited for drag racing, road racing, rallye, drifting, and pulling applications where a stock or street-oriented clutch simply won't hold up. SPEC clutches are engineered to the most advanced fabrication processes under strict tolerances, making the SMG004 a trusted choice for serious motorsport competitors.