I have two new-in-box 1-1/8" threadless headsets and a star nut left over from a headset installed on a carbon steerer (expander plug only!). All three of these starnuts are about 1-1/8" OD and would be a press fit into any 1-1/8" steerer OD. I don't know how you got a starnut too small to fit unless it was previously used.