Renthal 5240-520-51GPSI Twinring Grooved Rear Sprocket 51T 520 Chain Silver

The Renthal 5240-520-51GPSI Twinring Rear Sprocket is a 51-tooth, 520 chain pitch rear chainwheel engineered for off-road, motocross, and enduro applications. Backed by over 50 years of motocross drivetrain manufacturing expertise, the Twinring is Renthal's most durable rear sprocket — purpose-built for riders who demand longevity without sacrificing performance.

The Twinring's defining feature is its dual-material hybrid construction. The inner ring is crafted from high-strength, ultralight 7075 T-6 aluminum to keep overall weight to a minimum, while the outer ring is precision-formed from electroless nickel-coated steel for maximum wear resistance. The steel outer ring is heated to 200°C and pressed over the aluminum inner, creating a permanent interference-fit bond that lasts the life of the sprocket.

Key Features:

• 51-tooth, 520 chain pitch rear sprocket — silver anodized finish
• Dual-material Twinring construction — 7075 T-6 aluminum inner core bonded to electroless nickel-coated steel outer ring
• Precision CNC-machined to extremely tight tolerances for optimal chain engagement and concentricity
• Flat face design keeps the sprocket as narrow as a standard chainwheel while minimizing weight
• Self-cleaning mud grooves between every tooth on both sides to prevent dirt buildup and reduce wear
• Flat socket head screws add structural reinforcement during side impacts and eliminate contact with the chain guide
• Outlasts a standard all-aluminum sprocket by up to 3x, yet significantly lighter than an all-steel sprocket
• Silver anodized finish with multi-step anodizing process for corrosion resistance

The Renthal Twinring 5240-520-51GPSI delivers an ideal balance of low unsprung weight and extended service life, making it a top choice for off-road and enduro riders running a 520 chain who want to spend more time riding and less time replacing drivetrain components.