Spec Clutch SD89A Billet Aluminum Flywheel SFI Certified

The SPEC SD89A is a billet aluminum flywheel precision-engineered for high-performance and competitive racing applications. Weighing just 18 lbs, it delivers a significant reduction in rotating mass compared to a standard steel flywheel, resulting in faster engine revs, reduced drivetrain drag, and quicker throttle response.

Precision Manufacturing:

• CNC-machined to an industry-leading .001 inch tolerance — 10x tighter than the industry standard of .010
• Guarantees a perfectly flat clutch bedding surface for consistent friction disc engagement
• True rotational balance eliminates harmful dimensional runout, preventing engine vibration and power loss
• SFI certified for competitive and safety-critical racing environments

Aircraft-Quality Aluminum Construction:

• Body machined from tempered billet aluminum — either 6061-T6 or 2024-T3 — for maximum strength at minimum weight
• Features a rebuildable design with a replaceable 1/4-inch thick 1050 high-carbon alloy steel friction plate for long-lasting durability with any friction disc material
• Friction plate secured with aerospace-grade fasteners or stainless steel rivets for exceptional strength and corrosion resistance
• Heat-treated, pressed-on ring gear secured with grade-10 fasteners for longevity

Optimized Moment of Inertia (MOI):

• SPEC engineers each flywheel to specific inertia targets based on vehicle weight, power output, gear ratios, and intended use
• Lighter rotating mass reduces parasitic drivetrain loss, freeing up horsepower at the wheels
• Suited for drag racing, road course, drift, autocross, and other high-performance applications

Designed, hand-built, and tested in the USA, the SPEC SD89A aluminum flywheel pairs directly with SPEC clutch kits for a fully optimized clutch system. Its rebuildable construction and replaceable friction surface make it a long-term performance investment for serious competitors.