Vortex 313ZK-40 420 Aluminum Rear Sprocket 40T Off-Road Motocross

The Vortex 313ZK-40 is a high-performance aluminum rear sprocket featuring a 40-tooth count and designed for 420 pitch chains. Built for off-road and motocross riding, this sprocket delivers a significant weight savings over stock steel units, reducing rotating mass for improved throttle response and power delivery.

Key Features:

• Material: 7075 T6 aluminum alloy per Vortex specifications — maximum strength with minimal weight
• Chain Pitch: 420
• Tooth Count: 40T
• Construction: 100% CNC-machined in the USA for precise concentricity and consistent alignment
• Finish: Available in multiple anodized color options for corrosion resistance and custom styling
• Tooth Design: Optimized tooth profile minimizes drag for smoother chain engagement and extended chain life
• Part Number: 313ZK-40

Vortex Racing is a U.S.-based manufacturer with a long track record in professional motocross and road racing. Each sprocket is held to strict tolerances to ensure drop-in fitment and reliable performance under demanding conditions. The 313ZK-40 is a direct replacement upgrade for riders looking to reduce unsprung and rotating weight without sacrificing durability.