Spec Clutch SB46A Aluminum Flywheel SFI Certified

The Spec Clutch SB46A is a billet aluminum performance flywheel precision CNC-machined to a .001-inch tolerance — ten times tighter than the industry standard of .010. This exceptional precision delivers perfect rotational balance and a flat, true bedding surface for the clutch disc, reducing engine-robbing vibration and supporting smooth, high-rpm operation. The SB46A carries SFI certification, making it suitable for competitive and racing environments.

Constructed from aircraft-quality billet aluminum, this lightweight flywheel reduces rotating mass compared to stock cast steel units. Less rotational mass means quicker RPM buildup, faster throttle response, and more efficient power delivery from the engine to the drivetrain. SPEC engineers the moment of inertia (MOI) of each flywheel specifically for its application, optimizing the balance between acceleration response and drivability.

The flywheel serves three critical roles in the drivetrain: providing a consistent friction surface for clutch engagement, contributing appropriate inertia to manage the power-to-acceleration ratio, and maintaining true rotational balance to eliminate harmful runout at high rpm.

Key Features:

• CNC-machined to an industry-leading .001-inch tolerance (vs. .010 industry standard)
• Constructed from aircraft-quality billet aluminum for reduced rotating mass
• Rebuildable design with a replaceable steel friction plate for long service life
• Replaceable friction plate is formulated for optimum clutch bedding and holding power
• SFI certified for competitive and racing use
• Engineered MOI (Moment of Inertia) optimized for specific application performance
• Eliminates dimensional runout that causes vibration and power loss

The SB46A aluminum flywheel is an ideal upgrade for performance street driving, road course, drift, drag, and high-rpm racing applications where reduced rotating mass and precision balance are critical.