Spec Clutch SF50S-9 Billet Steel Flywheel SFI Certified - 1.1 9-Bolt 164-Tooth

The Spec Clutch SF50S-9 is a precision-engineered billet steel flywheel designed for high-performance and competitive driving applications. Machined from high-carbon billet steel, this flywheel delivers the consistency, balance, and durability demanded by serious drivers on both the street and track.

Precision CNC Manufacturing: SPEC flywheels are CNC-machined to an industry-leading .001-inch tolerance — ten times tighter than the industry-standard .010 tolerance. This precision ensures a perfectly flat clutch-seating surface, true rotational balance, and zero dimensional runout that could otherwise cause engine-damaging vibration and power loss.

Key Features:

• High-carbon billet steel construction for superior strength and durability
• 164-tooth ring gear with a 9-bolt pressure plate bolt pattern
• 14.240-inch flywheel diameter for proper fitment
• Replaceable steel friction plate specially formulated for optimum clutch bedding and holding power — making this flywheel rebuildable
• SFI 1.1 certified for use in competitive and sanctioned racing environments
• Internal engine balance compatible design
• Manufactured in the U.S.A.

The flywheel plays a three-part role in drivetrain performance: it provides a consistent friction surface for the clutch disc, contributes to proper rotational inertia that directly influences acceleration and drivability, and must maintain true rotational balance at all RPM levels. SPEC engineers each flywheel with a specific Moment of Inertia (MOI) tuned for the target vehicle's power output, gear ratios, and driving environment — making the SF50S-9 a purpose-built solution rather than a generic lightweight flywheel.

The replaceable friction plate extends the service life of the flywheel, allowing it to be rebuilt rather than replaced, making it a long-term investment for high-performance builds.