SRAM 12t X-Sync pulley for 1x drivetrains

thingiverse

There are dozens of jockey pulleys available on Thingiverse, but most of them feature the older 11t design. Recently, I managed to break two SRAM jockey pulleys for no apparent reason, despite my derailleur being fine. Replacement pulleys were a whopping $30 - it was time for me to add to the growing collection of Thingiverse jockey pulleys. SRAM thinks that jockey pulleys require the narrow/wide design that's supposed to improve chain retention on chainrings, but I'm not convinced it makes much of a difference. Still, I matched their design and duplicated it as closely as possible. The raw model is included, along with a split model that can be printed in two halves and then glued together using superglue. I've found cleaning up supports to be frustrating, so printing the pulley in halves and gluing them together has become my preferred method. This version is designed around the 626 bearing used by SRAM in their X-Sync pulleys, and includes press pieces for easily removing old bearings and pressing new ones into place. However, since the 626 bearing is less common, I'm planning to create a new version using the more widely available 688 bearing. That won't work seamlessly with SRAM hardware, though, so this design should still be useful. **Update 8/21/18:** After riding my mountain bike over 1750km (1100 miles) through winter, spring, and summer, I finally pulled off the lower pulley, which I had printed in PLA. Cleaning it up revealed that it was still in great condition, despite some noticeable wear on its surface. The only issue was a slight opening of the bearing bore, allowing the pulley to shift side to side and causing additional wear. I plan to recreate the pulley in Fusion 360 and address these issues in the redesign.