Spec Clutch SJ155 Stage 5 Performance Clutch Kit - Sintered Iron Full Face

The SPEC SJ155 Stage 5 Clutch Kit is SPEC's most aggressive single-disc performance clutch, engineered for extreme drag racing, pulling, and high-output competition builds. This race-grade kit utilizes a full-metallic sintered iron disc to deliver the highest possible friction coefficient available in a single-disc configuration.

At the heart of the Stage 5 is a solid, unsprung hub — unlike sprung-hub designs, there are no dampening springs to absorb drivetrain shock, which means maximum power transfer to the wheels. The hub features a 12-rivet construction and the entire assembly is heat-treated for strength and long-term durability under race conditions.

Kit Includes:

• High-clamp performance pressure plate
• Full-metallic sintered iron friction disc — full face, unsprung hub
• 26-spline input shaft compatibility (1.125 in. diameter)
• Release bearing and installation tool kit
• Flywheel not included

Key Features:

• Highest friction coefficient of any SPEC single-disc clutch stage
• Solid 12-rivet, heat-treated hub and disc assembly
• High-clamp pressure plate for maximum torque holding capacity
• Ideal for drag racing, pulling, and autocross competition
• Street-drivable but not street-friendly — harsh engagement characteristics
• SFI-approved clutch program

The Stage 5 is best suited for heavily modified or dedicated race vehicles where outright torque capacity and engagement aggression take priority over daily drivability. Due to the solid hub design, clutch chatter and drivetrain harshness should be expected in normal driving conditions — this kit is intended for race applications.