Bike Rear Derailleur Pulley 11T - 17T Jockey Wheel Guide Roller 13T Gold Description: Bike rear derailleur pulley is made of high quality ceramic bearing aluminum alloy material, whcich is anti-rust and , sturdy and durable. The inner ceramic bearing is ultralight and super lubricating, which can ensures its smooth working and provide you with a great using effect. The rear derailleur pulley is used on rear derailleur for chain transportation and speed changing, which is a necessary accessary for . Deep toothed guide wheel to reduce chain drop. Positive and negative wheel can effectively inhibit the horizontal swing of the chain, so that the speed is more accurate Easy to install, included a screw and 2 replaceable 4mm and 5mm bushing to enrich your installation choices. Specifications: Material: Aluminum Alloy, Ceramic Bearing Size: 11T - 41.4mm or 1.63inch 12T - 50mm or 1.97inch 13T - 50.7mm or 2inch 14T - 58mm or 2.28inch 15T - 59.7mm or 2.35inch 16T - 68mm or 2.68inch 17T - 66.8mm or 2.63inch Package Includes: 1 Piece Bike Rear Derailleur Pulley Wheel