The two halves of the unit bearing are pressed together.
They are held there by the stub shaft, trust me the press fit does not hold together with the tires on the ground and driving, usualy about 50 feet.

They get drug onto trailers and brought to me held togther with bubble gum and bailing wire, the knuckle ears for the caliper break off, and the caliper get destroyed.
and you get to see the remains of the inside of a unit bearing minus the ball bearings because those fall out all over the road.

If you think I'm making this up, take out your stub shaft and drive around for a bit, with oe size tires it might last a little longer, but 35"s or bigger,, good luuck.

SD