Bearings are what enable the gears to rotate effortlessly. They are typically created outside of bronze or brass, and they match into races (or grooves) inside the gearbox housing. Synchro rings have tooth on them that mesh While using the teeth over the gears, plus they also have friction materials https://filter-gearbox90172.ampedpages.com/the-ultimate-guide-to-filter-gearbox-61046197