Vortex 817ZK-42 Black Aluminum Rear Sprocket 42-Tooth

The Vortex 817ZK-42 is a 42-tooth black anodized aluminum rear sprocket designed for high-performance street and track use. Part of Vortex's ZK series, this sprocket features a striking black anodized finish with contrasting silver machined accents, combining race-proven engineering with aggressive aesthetics.

Vortex rear sprockets are 100% CNC manufactured in the USA from a specially formulated aluminum alloy developed to Vortex's own specifications. The lightweight construction reduces rotating mass for improved throttle response and more efficient power transfer to the rear wheel. The black anodized finish provides corrosion resistance while the Vortex patented tooth profile is engineered to maximize sprocket and chain longevity.

Key Features:

• 42-tooth rear sprocket for tuned gearing ratios
• Black anodized finish with contrasting silver machined accents
• Lightweight aluminum construction reduces rotating drivetrain mass
• 100% CNC machined in the USA to precise tolerances
• Specially formulated alloy per Vortex specifications
• Vortex patented tooth design for extended sprocket and chain life
• Designed for use with Vortex sprocket carriers (pattern 817)

The 817ZK series is designed for specific aftermarket wheel applications. Riders choose Vortex sprockets for their superior craftsmanship and the ability to fine-tune gear ratios for improved acceleration and top-end performance — an ideal upgrade over OEM gearing.