RENTHAL Ultra-Light Sprocket 518U - 420 (46 teeth) — Manufacturer part number: 518U-420-46GPBK. Designed for motocross, this rear sprocket made of 7075 T6 aluminum combines lightweight construction with precision machining for a responsive and durable final drive.
- Material: 7075 T6 aluminum, CNC machined in Manchester (U.K.).
- Weight: up to 66% lighter than steel (based on material comparison).
- Teeth: 46, shaped to optimize chain contact and torque transfer.
- Chain pitch: 420 — designed for standard 420 chains.
- Finish: black, wear-resistant surface treatment suitable for off-road conditions.
- Type: standard, mud-resistant version to facilitate dirt evacuation and limit buildup during muddy rides.
The UltraLight design focuses on tight tolerances and controlled concentricity to reduce vibrations and enhance the longevity of the drivetrain. Ideal for recreational racing and intensive training, it is particularly suitable for small displacement motocross bikes such as the KTM 65 SX (2025) and the GAS GAS MC 65 (2025), while remaining compatible with other models that accept a 420/46 sprocket.
