Built this uni with the help of Mos and someone from the forums!
You need more complex spacer to prevent bearings sliding.
If your current spacer isn’t good enough, ask me to model spacer for your frame.
What about using another set of bearing caps as spacers ?
They would not fit within the frame bearing groove but they will wrap the top of the bearing and the bolt will keep the whole thing solidly joined to the frame thanks to the flat surface in the bolt area…
This might also be a solution for the folks who wanted to squeeze a 32" wheel into a Hatchet.