Well, not sure about bearing brand. I lost the roller on my Nova flail and just ordered some replacement 2 flange bearings. You can see that the bearing seized and broke the cast holder and yanked the stub out of the roller. Hopefully, lesson learned and I’ll remember to lift and spin the roller before use.I have a Novatractor Flail. MFZ-155. We call it the park maker. The 3 pound hammers look a bit like metal bear claws and they wreck stuff I don't mow lawn, I mow weeds and brush, sticks, pine cones. It turns rough overgrown areas into mulched up useable areas like magic. The main unit is built in China, but it uses Comer transmission and SKF bearings, so the main moving parts are quality.
The hammers. This is why I picked Novatractor over anything else.
UCFL207 Cast Iron Oval Flange Bore Size 35mm