Setup my new 149 tit indys...one axle was machined weird (or not enough), it was difficult to get the wheels on (one more than the other), but not so bad I thought it to be a major issue, and once on, wheel is so difficult to get off the bearing will stay the axle when I yank the wheel off and it's impossible to get the bearing off...I've tried everything, started to bang off the bearing to no use, so now I've got a bronson ceramic stuck mid axle on a truck I can't fucking use, fucking livid right now.
Newer China-indys, no cross and 149 under the hanger.
Leaving it as is (yes those are hammer to truck rage marks (bearing still spins).
I have seen that a number of times over the years, almost always with rust getting in to things, so the axle with rust was thicker, which was resolved quite easily with a bit of Mob grip leftover wrapped around the axle and used like sandpaper. That same process may or may not work on that axle too, but doing that for about a minute usually gets enough material off the axle to be able to get the bearing on and off without too much trouble.
Note some bearings have wider centers than others too, which was interesting to note, as one brand just wouldn't fit at all but another brand fit easily with one random set of trucks that had thicker axles than usual.
Also had to deal with bearings rusted on to the axle too, and a couple that were stuck like that, even after one guy cut the whole wheel off to try to get at the bearing, but this is what worked the best:
Put the complete board on the side, that axle end down on the solid concrete ground and sit some grips, pliers or something over the bearing, almost gripping the axle but not quite. Then use the hammer and hit the grips in a downward motion as close to the axle as you can and that should result in your bearing staying in one piece and the grips forcing the whole bearing off the axle.
I have also used a short / medium flat head screwdriver jammed against the bearing core and axle and hammer, going more gently hitting on one side then the other until it has come off, from being in the same position (axle facing down and end on the ground) letting gravity do the work for you too.
Push the speed rings down so you are hitting / pressing on them too.
@Vitriol has the right way of it, only it is harder to get into that position and I try to always do things in the simplest way with the least amount of tools possible, given most of the issues are either at the shop or at a skatepark / spot where you might not have everything at your disposal.
Gnarred for effort though!