Vortex 635A-66 Aluminum 520 Rear Sprocket 66-Tooth Silver

The Vortex 635A-66 is a 66-tooth aluminum rear sprocket designed for the 520 chain pitch, built for riders seeking maximum gearing flexibility for stunt riding, track days, or performance street use. At 66 teeth, this is one of the largest rear sprockets in Vortex's lineup, delivering dramatic low-end torque multiplication and aggressive acceleration.

Key Features:

• 66-tooth rear sprocket for extreme low-end torque and acceleration
• 520 pitch chain compatibility
• CNC-machined from high-grade aluminum for lightweight, reduced rotating mass
• Vortex's patented tooth profile engineered to maximize sprocket longevity and smooth chain engagement
• 100% manufactured in the USA
• Silver finish — Vortex aluminum sprockets 55 teeth and above are available in silver

Vortex Racing rear aluminum sprockets are a top choice among performance and stunt riders. The reduced rotating mass compared to steel sprockets helps transfer more power to the rear wheel. The 635A-66 is a direct bolt-on replacement for compatible applications and pairs seamlessly with Vortex 520-pitch chains for a complete drivetrain upgrade.