Originally Posted by
The_Joe
Good to know. But I did take them apart a few months ago and so I think I might have missed one in the process of reassembly. I say this because it is a pretty big space and even through the noise is gone I know feel a very slight knock in the pedal. It seems like the bearings are colliding inside and I feel that momentum shift.
If the cone is correctly adjusted to a slight preload, the balls are each in constant contact with the axle and outer race. All the load is 100% radial through the balls, and there's no force pushing them apart on the bottom and against each other elsewhere. In use the gap will spread itself among the complement of balls, and there'll be no ball to ball contact (the grease ensurs that).
You'll note that I said "if the cone is adjusted correctly". That's because if the bearing is loose the balls ride on a smaller diameter part of the cone. Now the axle can shift off center eliminating the concentricity needed for the system to work as designed. The axle presses down between the balls forcing forcing them out to either side so they rub against each other. "Axle drop also sets up a vibration as each ball passing 6 O'clock has to lift the axle slightly to get by.