Vortex 313ZK-37 Aluminum Rear Sprocket 420 Pitch 37-Tooth Black

The Vortex 313ZK-37 is a lightweight, high-performance aluminum rear sprocket designed for 420-pitch chain drive systems on small-bore motocross and off-road motorcycles. Built to replace heavy OEM steel sprockets, it delivers measurable weight savings that reduce rotational mass and improve throttle response.

Key Features:

• 37-Tooth / 420 Pitch: Engineered for 420-chain drivetrains common on mini and small-displacement motocross bikes
• 7075-T6 Aluminum Construction: Aerospace-grade alloy provides maximum strength with minimal weight
• Black Anodized Finish: Anodized first, then CNC-machined for a durable finish with silver contrast highlights
• 100% CNC Manufactured: Precision-machined in the USA to tight tolerances for consistent alignment and reduced drivetrain wear
• Patented Tooth Design: Vortex's unique saber-tooth groove geometry minimizes friction and extends both sprocket and chain life
• Direct Bolt-On Replacement: No modifications required for compatible applications

The 313ZK-37 is the preferred choice for motocross and off-road riders seeking a performance upgrade over stock gearing. The reduced rotating mass improves power delivery and acceleration feel, while the corrosion-resistant anodized finish holds up under harsh riding conditions. Part number 313ZK-37 denotes the 313 sprocket series, ZK black anodized finish, and 37-tooth count.