Control Tech Rage/Rage OS D Crankset Chainring Review Posted by GiantPandaisy June 19, 2018 in Drivetrain Components Chainrings:24/27/28/29/40/42/44T BCD:104/64mm Material:AL7075 CNC Crankset Chainring for Rage D/Rage OS D, Material:AL7075 CNC BCD:104/64mm, chainrings:24/27/28/29/40/42/44T. Control Tech Cycling Outdoor Recreation Parts & Components Sports & Outdoors