Uneven Thrust Loads on Needle Roller Bearings

[Kevin Sevcik]

As long as you have two bearings supporting the shaft, it won't be that much of a problem even if they aren't on opposite sides of the shaft. Of course, the more seperation the better, but 4" can't be THAT bad. wil a ~200ft-lb moment, it'd put less than 1000 lbs of radial force on a bearing. MSC actually has some angular contact bearings that look more than capable of dealing with that kind of load.
Also, think about way to counterweight the thing so it doesn't apply that kinda moment in the first place.