Mountain Bicycles Pulley Wheel — 12T 11-speed derailleur repair set Key benefits Improves shifting precision and reliability: 12-tooth pulley wheels reduce friction and stabilize chain tension to deliver smoother, more consistent gear changes. Durable, low-maintenance construction: molded ABS pulley wheels with sealed bearings run freely and resist wear and contamination for longer service life. Broad compatibility for repairs: designed as a replacement set for 11-speed derailleur systems, making it easy to restore performance after wear or damage. What this product does for you Restores precise shifting when jockey wheels are worn or noisy. Reduces drivetrain drag so pedaling effort is more efficient, especially when climbing or accelerating. Keeps chain tension steady through gear changes, lowering the risk of mis-shifts and chain derailment. Specifications and features Type: Pulley wheel repair set for rear derailleur Tooth count: 12T (12 teeth) Compatibility: 11-speed (11-gang) drivetrains Material: ABS pulley body with sealed bearings Function: Guides chain, reduces friction, maintains consistent tension during shifting Practical use scenarios Mountain biking on steep, technical climbs where smooth, reliable shifting is essential to maintain momentum. Daily commuting in mixed traffic and stop-and-go urban conditions where precise shifting improves control and reduces wear. Routine workshop or roadside repairs to replace worn jockey wheels and quickly restore drivetrain performance. Why choose this set Direct replacement designed for excellent compatibility with 11-speed derailleurs. Simple upgrade/repair that has an immediate, noticeable effect on shifting quality and drivetrain efficiency. Balanced combination of durable ABS construction and sealed bearings provides smooth operation without frequent servicing. Installation tip Replace worn pulley wheels in matched pairs and follow the derailleur manufacturer’s torque and orientation instructions to ensure optimal performance.