24 spoke rims. The wheel has been true and trouble free since new. Tough to come up with hypotheses for cracks on the inner holes. Maybe like the unground weld portals on the new San Francisco transit center’s cracked beams, perhaps the drilling left microscopic stress riser points that initiated cracks after repeated rim flex cycles? Dunno, I’m grasping at straws, but I did send a note and picture back to Spinergy.