[sanddrag]

Originally Posted by DampRobot

The major difference is that you don't rely on 1/2" hex bearings, which have had defects and gone out of stock in the past. Of course, it depends on you being able to broach 7/16" hex and have access to a active tooling lathe to make your wheel shafts.

This is exactly it: the desire to use standard R8-2RS bearings in our bearing blocks. Also, I should note that we use 7/16" hex on the sprocket side as well. While a live-tooled lathe would be nice, we get by with doing our hexes (and snap ring grooves) on a 3 axis CNC mill, with the axle standing vertical in a 5C collet holder. It works great. You could even mill hexes with a hexagonal 5C collet holder on a manual mill.