Renthal – Renthal Rear Sprockets - Yamaha - 520 Pitch - Street, including the 18-19 Yamaha MXT 850 Niken hard anodized 520 rear sprocket in a 40P tooth count. This is a focused, road-oriented corner of the Yamaha sprocket range, built for a rider who wants sharper acceleration from a big-bore street triple without pulling the engine apart. Converting to 520 pitch and a 40-tooth rear reduces drivetrain weight compared with a heavier stock chain and steel sprocket, and rotating mass at the rear wheel is the weight that costs the most in acceleration and in how quickly the chassis changes direction. The hard anodized 7075-T6 aluminium construction is what makes a light street sprocket viable, resisting the tooth wear that a torquey twin-cylinder engine and daily road miles would inflict on a plain alloy part. Accurate CNC tooth profiles run quietly with a fresh chain and keep engagement smooth, so throttle inputs feel direct rather than notchy. It is a straightforward change that wakes up roll-on response while keeping highway cruising manageable. Pairing the sprocket with a quality 520 chain keeps the drivetrain quiet and the new teeth accurate for the long term.