Attributes . All 520 Steel Quick Acceleration kits feature RKs premium, lightweight RX or XW-ring sealed racing chain in either gold or natural finish. Kits include a premium Driven C45 steel alloy black case hardened rear sprocket paired with Driven C45 steel case hardened and quenched front sprocket. RKs 520 Steel Quick Acceleration Race Kits combine the enhanced performance of race gearing and durability of steel components. Kits include a one-tooth-smaller-than-OE front sprocket. Experience quicker starts and quickest to your bikes red line in every gear without sacrificing normal ride, handling or longevity. OE Front Sprocket Size: 15. OE Rear Sprocket Size: 45/44. Kit Front Sprocket Size: 14. Kit Rear Sprocket Size: 45. Chain Type . Values