BBInfinite's Shimano 12T pulleys have rock solid chain control, meaning crisper shifts while Ceramitech bearings channel all your hard work to the ground.
Each road bike pulley cog set features DELRIN® 510GR construction, a fiber reinforced polymer specially suited to high strength situations where resistance to deflection is paramount, such as every time you shift. The Ceramitech bearings are in-molded for absolute security and durability as well as ease of maintenance.
These pulleys are compatible with:
5800-series 105, GS cage only
6800-series Ultegra, GS cage only (mechanical and Di2)
R8000-series Ultegra (mechanical and Di2)
R9000-series Dura Ace GS cage only (mechanical and Di2)
R9100-series Dura Ace (mechanical and Di2)
These pulleys DO NOT FIT 12spd R9200-series Dura Ace or Ultegra 8200-series group sets.