BKCJ-0190 | 11 Tooth Derailleur Pulleys for 11 Speed SRAM Derailleurs (4mm Bolt upper/5mm Bolt lower)

BKCJ-0190 - 11 tooth, Zero Ceramic Hybrid Bearing, Machined Delrin Derailleur Pulleys for 11 speed SRAM Derailleurs (4mm bolt upper/5mm bolt lower) Precision machined Black Delrin Derailleur pulleys featuring Zero, Black-Oxide treated, Ceramic-Hybrid Radial Bearings for enhanced shifting performance and longevity. Designed and manufactured for performance, these pulleys feature CN (tight clearance) bearings in the upper pulley to maximize shifting accuracy and C4 (loose clearance) bearings in the lower pulley to allow for chain-line movement. 500 AF Delrin pulley material features a high mechanical tensile strength and rigidity, natural lubricity, high resistance to moisture, caustic chemicals and UV makes these pulleys highly durable, rigid and very smooth. Delrin also machines very cleanly and precisely. The inherent lubricative qualities of this Teflon-infused material greatly reduces friction when it interfaces with the bicycle chain. When compared to other pulley materials, 500 AF Delrin with Teflon, offers significantly less drag than pulleys machined from aluminum or titanium. Enduro Zero Ceramic-Hybrid Bearings featuring Black-Oxide treated 52100 High-Carbon Chromium alloy races paired with grade 5 Silicon-Nitride Ceramic Balls with 90% fill, high-pressure, water-proof grease. Si3N4 ceramic balls reduce bearing wear and increase bearing life by eliminating steel on steel contact within the bearing. Black oxide/magnetite treatment to the races provides an extra level of corrosion resistance and extended worry-free performance. The eleven tooth size and profile with 4mm bolt-hole upper pulley and 5mm bolt-hole lower pulley are designed as an upgrade for most 11 speed SRAM derailleurs. Enduro Derailleur Pulleys are available in a number of configurations and performance levels and are all are proudly precision manufactured in the USA.