Spec Clutch SV21A Aluminum Flywheel SFI-Certified CNC Billet

The SPEC SV21A is a precision-machined aircraft-quality billet aluminum flywheel engineered for high-performance and competitive racing applications. CNC manufactured to an exceptionally tight .001-inch tolerance — ten times tighter than the industry-standard .010 — this flywheel delivers perfect rotational balance and a perfectly flat clutch disc bedding surface. The SV21A carries full SFI certification, making it suitable for sanctioned racing environments.

Key Features:

• Aircraft-grade billet aluminum construction for a lightweight, high-strength alternative to steel flywheels
• CNC machined to .001-inch tolerance — 10x tighter than industry standard — for superior balance and runout elimination
• Replaceable steel friction plate made from a specially formulated friction-enhancing alloy for optimum clutch bedding and clamping power
• Rebuildable design — replace the friction surface without replacing the entire flywheel
• SFI certified for use in competitive and sanctioned racing environments
• Optimized moment of inertia (MOI) engineered by SPEC to maximize power delivery and acceleration for the intended application
• Eliminates dimensional runout that causes engine-damaging vibrations and parasitic power loss

The flywheel is one of the most critical components in the drivetrain, performing three essential functions: providing a consistent friction surface for the clutch disc, controlling rotational inertia to balance power-to-acceleration ratios, and maintaining true rotational balance at high RPM. SPEC's aluminum flywheel reduces rotational mass compared to steel units, allowing the engine to rev more freely — ideal for high-revving performance and racing builds where throttle response and acceleration are priorities.