Campagnolo recommends their genuine replacement parts for optimal running performance with lower chain noise and protecting your warranty status. The Record 12-Speed Rear Derailleur Pulley Set includes the 12T upper and lower pulley wheels you require to maintain your R12 Rear Derailleur to it's optimal state. The composite pulleys are quite durable, but with enough mileage combined with riding conditions the pulleys will wear. The teeth of the pulleys are pre-shaped for functional reasons, but if you check when performing drivetrain cleaning, over time you will see wear develop.

With the large cassette options available in 12-speed, Campagnolo redesigned both pulleys for the specific requirements of each location, and you can see the tooth profiling on the Upper Pulley is taller and narrower to deliver better chain interaction over a wider cassette cog range. The Lower Pulley retains some of the familiar shorter depth teeth with more mass, as the lower pulley requires less chain hold, but wears faster than the Upper.

You should always you should replace the two pulleys at the same time, and it doesn't hurt at all if this is performed when you change your chain and cassette for overall optimal performance and reduction of uneven wear. With the Record 12, Campagnolo outfitted both pulleys with a steel bearing system (silver covers) for better performance than bushings or a bearing/bushing combination This kit provides the two pulleys and all new hardware to replace existing parts. Please note directional arrows on the pulleys for proper installation.