I have a Cannondale Trail SL SS from 2014 or so, and I'm having trouble figuring out what to replace the upper headset bearings with (they are knackered). The fork is the one the bike came with, a Cannondale Fatty with a 1.5in straight head tube. The headset that came with the bike was likely the Cannondale KP191, this is (I think) semi-integrated, in that the lower bearings are in a cup that is pressed into the headtube, but the upper bearings are pressed directly into the headtube.
The lower bearings wore out some time ago and at that point I replaced the lower cups with a Cane Creek 40-series EC49-40 Bottom Assembly. This worked fine, and the replacement bearings for this seem to be easy to obtain (they're standard, and just pop in/out of the cups).
The issue I'm having is with the top. The existing bearings looks like this:
(The inner part of the bearing separated from the rest, which may or may not be visible in the picture.)
Maybe a better picture is here:
(the upper bearings are the third from the right in the last row).
I can't seem to source a new KP191 anywhere (they are sold out, which makes me think they aren't made any more), I'm not sure what to search for when it comes to just replacing the broken upper bearings (they have a flange on them, no number I can see, so difficult to search for).
The question is: how can I find replacement bearing?
If the answer is "you can't", what are my alternatives? I've spent an hour or so trying to figure out what replacement headset might be (I only need the upper), but they all seem to have upper and lower cups for the bearings. Can I actually fit one of these? I.e. press cups into the headtube (where the bearings are pressed in directly just now) and seat the bearings in those? Or what?