Spec Clutch SF66A SFI-Certified Aluminum Flywheel

The Spec Clutch SF66A is a billet aluminum flywheel engineered for high-performance and competitive motorsport applications. CNC-machined to an industry-leading .001-inch tolerance—ten times tighter than the industry standard of .010—this flywheel delivers exceptional balance, a perfectly flat clutch disc bedding surface, and carries full SFI certification for use in demanding racing environments.

Key Features:

• SFI Certified — meets stringent safety standards required for sanctioned competition
• CNC Machined to .001 Tolerance — ten times more precise than the industry standard, ensuring perfect rotational balance
• Aircraft-Quality Billet Aluminum Construction — lightweight design reduces rotating mass for faster engine response and acceleration
• Replaceable Steel Friction Plate — features a specially formulated friction-enhancing steel insert optimized for clutch bedding and maximum holding power
• Rebuildable Design — cost-effective serviceability for extended product life
• Zero Dimensional Runout — eliminates engine-damaging vibrations and power-robbing harmonics for smooth, consistent RPM operation
• Optimized Moment of Inertia (MOI) — weight and dimensions are research-engineered to maximize power transfer and vehicle performance

The flywheel plays a critical role in clutch system performance, contributing in three key ways: providing a consistent friction surface for the clutch disc, managing rotational inertia to balance power and acceleration, and maintaining true balance at all RPM levels. The SF66A's aluminum construction offers a lightweight option ideal for performance street and race builds where reducing rotating mass is a priority. Spec's extensive R&D into flywheel dimensions and weights ensures the SF66A is optimized to suit a wide range of driving and racing applications.