Spec Clutch SB905 Stage 5 Performance Clutch Kit

The SPEC SB905 Stage 5 Clutch Kit is SPEC's highest-rated single-disc performance clutch, engineered for extreme racing applications including drag racing and tractor pulling. Built around a full-metallic sintered iron disc with the highest possible friction coefficient, this kit delivers maximum holding power and instant, aggressive engagement for serious competition use.

The Stage 5 uses a rigid, unsprung iron disc assembly paired with a high-clamp pressure plate to ensure zero power loss under severe load. The solid hub features 12-rivet construction and the entire assembly is heat-treated for exceptional strength and durability under race conditions. This is SPEC's top single-disc stage — designed for purpose-built race vehicles where driver comfort is secondary to outright performance.

Kit Includes:

• High-clamp performance pressure plate
• Full-metallic sintered iron rigid disc assembly
• Release bearing
• Installation tool kit

Key Features:

• Full-metallic disc with maximum friction coefficient for extreme torque capacity
• Solid 12-rivet hub construction for rigid, no-slip power transfer
• Heat-treated disc and hub assembly for strength under sustained race loads
• High-clamp pressure plate for aggressive clamping force
• SFI approved — meets racing sanctioning body requirements
• Designed, hand-built, and tested in the U.S.A.

Intended Use: Drag Racing & Pulling. The Stage 5 is a race-only clutch. Due to its rigid disc and harsh engagement characteristics, it is not suitable for street driving. For street/strip applications, SPEC recommends Stage 1 through Stage 3+.