Would open or flanged ball bearings be better for this application?

[s09]

Hey all, recently found this site about ball bearings and have a question:

http://www.mcmaster.com/#standard-ball-and-roller-bearings/=ecllbn

I have an application that will have a gear sit on top of the ball bearing as it spins (the weight won't be too large, don't want it to be), what would be the better options? Open ball bearings? Flanged ball bearings? Something else?

 

[Unrest]

You need to work out the thrust (axial) load as well as the radial load, and find bearings that can support them. Also consider misalignment and speed. Try SKF's site, it has pretty comprehensive tools to select a bearing.

The ones with the covers can have grease retained in them. If it's open you'll need to contain the grease or oil some other way.

The flange is kind of secondary. Depends how you prefer to mount it.