Vortex 491ZK-40 Black 40-Tooth 520-Pitch Aluminum Rear Sprocket

The Vortex 491ZK-40 is a 40-tooth, 520-pitch black anodized aluminum rear sprocket designed for high-performance motorcycle applications. CNC-machined from premium 7075-T6 aluminum and finished with a hard black anodized coating, this sprocket delivers an ideal combination of lightweight construction and long-lasting durability.

Key Features:

• 520-pitch chain compatibility — designed for OEM 520 applications or suitable 520 conversions
• 40-tooth rear sprocket — optimized for balanced acceleration and top-speed performance
• 7075-T6 billet aluminum construction — specially formulated alloy per Vortex specifications for superior strength-to-weight ratio
• 100% CNC manufactured in the USA — machined to precise tolerances for concentricity and quiet operation
• Black CAT5 anodized finish — hard anodized with black dye and PTFE coating for added lubricity, corrosion resistance, and durability
• Vortex patented tooth design — unique saber tooth grooves increase sprocket longevity and improve chain engagement
• Lightening holes — strategically placed cutouts reduce rotating mass for improved throttle response and acceleration

The Vortex 491ZK-40 is a direct upgrade over heavy OEM steel sprockets. By reducing unsprung and rotating mass, it delivers a noticeable improvement in acceleration and handling response. Built to the same standards trusted by professional road racers, this sprocket is an excellent choice for street riders and track enthusiasts alike.