Shimano ceramic derailleur pulleys

Shimano 11 tooth derailleur pulleys

1 - Upper w/SB-607C sealed ceramic bearing

1 - Lower w/SB-607C sealed ceramic bearing

• Evolution Ceramic bearings are hybrid design containing Grade 5 Silicon Nitride (Si3N4) bearings. Races are ABEC 3, hardened chrome steel, cryogenically treated to align the grain structure maximizing the life of the race.
• Grade 5 Si3N4 bearings are twice as hard as steel bearings
• 70% stiffer, 75% smoother, 60% lighter
• Dual medium fit rubber seals to protect from the elements
• Kyodo Yushi SRL grease 30-40% fill rate