<Disclaimer!: I'm not an expert on these by any means.>
Don't cartridge-bearing setups have nuts on the axle whose purpose is to establish some (adjustable) compression loading of the bearings? Seems to me that I've read that, here, or in Mechanics forum. The bearings themselves are not that expensive, assuming that you've got a standard size. Pressed-in, obviously, so one needs a puller to remove them, and quite possibly a press to install.