Originally Posted by
krfarstad
I know it says everywhere that the ball size is 1/4", but to me that is obviously not true since I could fit only 8 of the old balls, and the axle was snug, while I could barely fit 9 1/4" balls, but with a lot of play in the axle. I don't possess tools that allow me to measure the sizes with sufficient accuracy to be able to tell them apart.
I can almost guarantee that I'm not doing it wrong. I did try with the new 1/4" balls and then with the old balls, and the difference was very clear. The balls are not the same size, although the size difference is small.
How did you test-fit the balls in the hub? I would recommend putting in a bead of grease in the race, placing the balls in the hub, then place the cone on top to push the balls into the correct position with regard to the cone and race. You should see where they sit, and you should be able to nudge them around to fit 9 balls on each side.
I've rebuilt Shimano hubs this way for 30+ years. The rear hubs have always had 9 1/4" balls.