Shimano Ultegra 6800 11-SPEED Cogs You tear around in the 53, and the 11 or 12 out back. This is for sure, because nobody can keep your wheel when you wind it up. When it's time to replace that 11 or 12 on your 11-speed rig, to get that shifting response and pull back, here's your cogs. Genuine Shimano replacement parts, for Ultegra 6800 11 speed. Shimano Ultegra 6800 11-SPEED Cogs Specifications: Contents: Single replacement cog Designed for Ultegra 6800 11-speed Note position of cog | Shimano Ultegra 6800 11-Speed Cog 11-Speed 11T 1ST Position Cassette Cog