Ok I got it. Thanks
But is this for all brands? Which brand do you got?
Mine were second hand so i don't know the brand the brand.
You save weight from the inner diameter on all bearings available now (9117622)
But there are also some design variations on the main flange. (where the disc is lying flat) which can show bosses or not but i don't know if they changed flange thickness .
No bosses
Or with bosses
visually, it seems that the part without bosses has a thicker flange to keep the same threaded length and then, should be heavier.
i know that FAG bearings are a "no bosses" design.