The Helix Race 107 BCD Chainring is a high-value quality upgrade for Gravel and Road Cyclists using 4-bolt 107 BCD cranks such as SRAM(R) XPLR or Power Meter Cranks like Quarq Force or Rival. Take full advantage of e*thirteen's widest range cassettes by dropping 2 teeth or more in chainring size with our smaller 38, 40, and 42T sizes. A combo that supports steeper climbs and faster descents. Helix Race 107 BCD rings are forged from long-wearing 7075 alloy and CNC optimized for stiffness, lightweight, and chain-retaining performance. Black & grey color options to coordinate with e*thirteen 9-45T and 9-50T cassettes. Like all e*thirteen chainrings, they feature cross-compatible tooth profiles, switching seamlessly between SRAM(R) or Shimano(R) 11 and 12-speed drivetrains for absolute build freedom. Chainline is determined by SRAM(R) crank assembly, 45mm for normal width cranks, 47. 5mm for wide cranks.