[C. Ludwig]

The bearing will "fit" any gear. However, you need the galley machined into the inner circumference of the gear for the multiple windows of the bearing to be effective. The 3rd gen gears have the galley machined in from the factory. You can also have the earlier gears macined. The 3rd gen multi-window bearing has the same 360* oiling as the 3-window race bearing, but its a lot cheaper. You can buy a new Renesis gear with bearing for not much more than the price of the 3rd gen bearing.