[j windpicker]

The bearings on the non-drive side won't stay inside the cup and as a result my axle/crank arms slide side-to-side. I can't seem to get them (bearings) to sit as deep in the cup as the drive-side bearings. Anyone else ever have this problem, and what was the fix?

 

[DavidMakalaster]

Sounds like you don't have the right number of spacers between the cups and bottom bracket shell. How wide is your BB? How many spacers are on there? Do you have a chainguide or BB mounted derailleur?