SRAM Rival 1x XPLR Wide Crank Arm Assembly - 172.5mm, 12/13-Speed, 8-Bolt Direct Mount, DUB Spindle, Black, E1SRAM has taken aluminum to another level. Careful engineering has resulted in crankarms that optimize stiffness to weight ratio, with material only where it's needed 8 bolt interface compatible with power and non power AXS spiders and integrated chainrings (Chainring and spider sold separately) DUB bottom bracket adds durability and simplicity (Bottom bracket sold separately) Aluminum arms optimized for stiffness and light weight 150mm Q factor 47.