Sram 10 spd og1090 redblack cassette the main cogset of the og 1090 cassette is machined out of a single forged form that is heat treated and then shaped in a complex series of cnc guided operations weight stiffness and strength wise the og 1090 cassette delivers titaniums weight with solid steels superior strength and stiffness lightweight innovative cncd chromoly steel construction durable 35 harder than titanium stiff 15 stronger than its competitor openglide technolo