What is the difference b/w dropout diameter(9mm) and 3/8"(9.478mm) Tpi bicycle axles
I just checked two frames and forks drop outs. They all measured at least 9.5mm. They all allowed a 3/8" bolt to pass through. If you are having doubts about your particular frame, get a 3/8" bolt and see it fits. You also need to verify that the nuts will sit correctly in the front fork.The nut must sit flat on the fork not on top of the safety tabs (also called lawyer lips).